(CNN) At least 35 protesters were killed and hundreds injured Monday in Khartoum when the Sudanese military opened fire to break up a sit-in, according to a local doctors' union.

The Central Committee of Sudan Doctors (CCSD) said critically injured patients are still in operating rooms and intensive care. The Sudanese military has denied any involvement.

Sudanese Attorney General Maulana Al-Walid Sayed Ahmed Mahmoud announced that a committee had been created to investigate "the events" that took place in the area of the armed forces' general command in Khartoum, state media outlet SUNA reported.

The committee will be made of up of officials -- including the heads of public prosecution, senior prosecutors, police representatives and representatives of the military judiciary, the attorney general said.

However, similar vows to investigate protester deaths during the rule of ousted former President Omar al-Bashir were insufficient to appease demonstrators at the time, and the committee's creation does not appear likely to mollify them now.

Eyewitnesses say security forces shot at protesters

Multiple eyewitnesses told CNN that security forces -- the police and the paramilitary Rapid Support Forces -- shot at protesters with live fire. Several videos also showed security forces beating people with sticks. The Sudanese military has moved to forcibly disperse protesters since April 11.

The CCSD also said earlier on its Facebook account that casualties were hit by "live bullets." The group said security forces surrounded hospitals where wounded and bodies were taken.

Those killed include an 8-year-old, the CCSD said. It said that more than 116 injured people were in several Khartoum hospitals.

A Sudanese protester uses paving stones to block Street 60 as military forces tried to disperse a sit-in on June 3, 2019.

A spokesman for the Sudanese Transitional Council said that the military "didn't disperse the sit-in by force" but that the security crackdown was instead on a gathering in a nearby "dangerous" area.

Mobile internet was also shut down in Sudan on Monday, several sources on the ground told CNN. Services then partially resumed on MTN -- one of Sudan's three mobile networks -- with intermittent and slow connectivity.

Opposition groups have relied heavily on social media to mobilize protesters, helping to unseat al-Bashir in April, then opposing the interim military council that has ruled the country since the coup.

In response, Sudanese Professionals Association (SPA), the group which has spearheaded the protests, called on people to press on with demonstrations and for telecommunications workers not to "succumb to pressure" by the ruling military council.

Protesters congregated outside the Defense Ministry in Sudan's capital Khartoum and other main streets.

Burning tires, black smoke and gun shots

Small fires and billowing clouds of black smoke could be seen in video taken in the capital. Other video showed people fleeing as guns went off. Protesters were also seen burning tires after security forces attempted to break up a sit-in.

Deema Alasad, a 25-year-old dentist from Khartoum, who took part in a sit-in outside the military headquarters, said the government's paramilitary force, as well as members of the intelligence and security services, arrived in the area early in the morning.

"They hit us and then they started shooting live ammunition, after putting the entire sit-in under siege," she said, describing the gunmen as "snipers."

Sudanese forces are deployed around Khartoum's army headquarters on June 3.

One woman, who asked not to be named, filmed video of a man lying on the ground, his arms trying to shield him from the blows of security forces who were beating him with sticks.

"I saw security forces chasing a car and stop it by force at gunpoint and hit the driver and his companion with sticks. And one of them yelled at me to stop recording. I filmed it from my window at 7:23 am," she told CNN.

Alasad said the protesters were "unarmed civilians."

"It is our right to protest and our right to express that we don't accept what is going on," she said.

Activist Fathi Abdo told CNN he witnessed around 20 people getting shot on Khartoum's main streets and near army headquarters, where protesters have staged a mass sit-in for months.

Opposition suspends talks

The Sudanese opposition suspended talks with the ruling body after Monday's crackdown. "We have halted all political communication and negotiations with the putschist council," said the Declaration of Freedom and Change Alliance -- an umbrella group for opposition groups and protest leaders.

"The leaders of this council are criminally responsible for all the bloodshed that took place since April 11th," the statement added. The opposition leaders vowed to take the generals to court.

Photos: In pictures: Sudan in transition Sudanese civilians atop a train join in celebrations over the signing of a deal that paves the way for a transitional government in Khartoum, Sudan, on Saturday, August 17. Hide Caption 1 of 43 Photos: In pictures: Sudan in transition Sudanese protest leader Ahmad Rabie, center right, flashes the victory gesture alongside Gen. Abdel Fattah al-Burhan, the chief of Sudan's ruling Transitional Military Council, center left, during a ceremony where they signed a constitutional declaration. Hide Caption 2 of 43 Photos: In pictures: Sudan in transition Sudanese men embrace outside the Friendship Hall in Khartoum where generals and protest leaders signed a historic transitional constitution, paving the way for civilian rule in Sudan. Hide Caption 3 of 43 Photos: In pictures: Sudan in transition Sudanese protesters celebrate in the streets of the capital, Khartoum, after ruling generals and protest leaders announced they have reached an agreement on a new governing body Friday. Hide Caption 4 of 43 Photos: In pictures: Sudan in transition African Union envoy to Sudan Mohamed al-Hacen Lebatt, second from left, shakes hands with an army general following a press conference announcing an agreement was reached. Under the terms, the military council will be in charge of the country's leadership for the first 21 months. A civilian administration will rule the council during the following 18 months. Hide Caption 5 of 43 Photos: In pictures: Sudan in transition Relatives of three Sudanese men who were found dead with bullet wounds mourn near their bodies in the city of Omdurman on July 1. Hide Caption 6 of 43 Photos: In pictures: Sudan in transition Protesters run from a police van that drove through a crowd on June 30 in Khartoum. The protesters faced off with armed forces on a main road leading to the airport. Hide Caption 7 of 43 Photos: In pictures: Sudan in transition A protester reacts to tear gas on June 30. Hide Caption 8 of 43 Photos: In pictures: Sudan in transition Sudanese protesters march in a mass demonstration against the country's ruling generals in the capital's twin city of Omdurman on June 30. Hide Caption 9 of 43 Photos: In pictures: Sudan in transition Tear gas fumes are seen amid a demonstration in Khartoum on June 30. Hide Caption 10 of 43 Photos: In pictures: Sudan in transition People chant slogans as a young man recites a poem, illuminated by mobile phones on June 19. Hide Caption 11 of 43 Photos: In pictures: Sudan in transition Mohamed Hamdan Dagalo, deputy head of Sudan's ruling Transitional Military Council (TMC) and commander of the Rapid Support Forces (RSF) paramilitaries, center right, waves a baton as he rides through supporters in Qarri, north of Khartoum, on June 15. Hide Caption 12 of 43 Photos: In pictures: Sudan in transition Sudan's Transitional Military Council spokesman Shams-Eddin Kabashi, right, speaks during a press conference at the Presidential Palace in Khartoum on June 13. Sudan's ruling military council admitted that it had ordered the dispersal of a Khartoum sit-in, which left more than 100 dead. Hide Caption 13 of 43 Photos: In pictures: Sudan in transition Protesters block a street with bricks and burning tires as military forces attempt to disperse a sit-in outside the army headquarters in Khartoum, Sudan, on Monday, June 3. More than 100 protesters were killed when the military opened fire to break up the sit-in, according to a local doctors' union. Hide Caption 14 of 43 Photos: In pictures: Sudan in transition Sudanese forces are deployed around Khartoum's army headquarters on June 3. Hide Caption 15 of 43 Photos: In pictures: Sudan in transition Protesters gather for a sit-in outside the military headquarters in Khartoum on May 19. Hide Caption 16 of 43 Photos: In pictures: Sudan in transition Gen. Mohammed Hamdan Dagalo, the deputy head of the military council that assumed power in Sudan, prays during a Ramadan event in Khartoum on May 18. Hide Caption 17 of 43 Photos: In pictures: Sudan in transition Sudanese army soldiers gather as people rally in front of the Presidential Palace in downtown Khartoum on May 18. Hide Caption 18 of 43 Photos: In pictures: Sudan in transition Protesters wave national flags at a sit-in outside the military headquarters in Khartoum on May 2. Hide Caption 19 of 43 Photos: In pictures: Sudan in transition Demonstrators attend Friday prayers outside the army headquarters on April 19. Hide Caption 20 of 43 Photos: In pictures: Sudan in transition Protesters shout slogans as they carry a soldier flashing the victory sign outside the army headquarters on April 18. Hide Caption 21 of 43 Photos: In pictures: Sudan in transition Protesters participate in a sit-in in Khartoum on April 17. Hide Caption 22 of 43 Photos: In pictures: Sudan in transition Demonstrators rally near the military headquarters in Khartoum on April 15. Hide Caption 23 of 43 Photos: In pictures: Sudan in transition Lt. Gen. Omar Zain al-Abdin, head of the Sudanese military council's political committee, addresses journalists in Khartoum on April 12, one day after Bashir was ousted. Hide Caption 24 of 43 Photos: In pictures: Sudan in transition Demonstrators cheer on April 11, after an announcement that Bashir had been detained "in a safe place." Hide Caption 25 of 43 Photos: In pictures: Sudan in transition A protester kisses a soldier on the head during a rally in Khartoum on April 11. Hide Caption 26 of 43 Photos: In pictures: Sudan in transition Protesters cheer outside the Defense Ministry in Khartoum on April 11. They were demanding that Bashir step down. Hide Caption 27 of 43 Photos: In pictures: Sudan in transition Sudan's defense minister goes on television April 11 to say Bashir's government has been dissolved. Hide Caption 28 of 43 Photos: In pictures: Sudan in transition Demonstrators stand on a military vehicle April 11 as they cheer and flash the sign of victory. Hide Caption 29 of 43 Photos: In pictures: Sudan in transition A billboard in Khartoum bears an image of Alaa Salah, a Sudanese woman who became the face of anti-government demonstrations. Hide Caption 30 of 43 Photos: In pictures: Sudan in transition Demonstrators block the vehicle of a military officer on April 11. Hide Caption 31 of 43 Photos: In pictures: Sudan in transition Demonstrators chant slogans as they gather in a street in central Khartoum. Hide Caption 32 of 43 Photos: In pictures: Sudan in transition Salah, the woman propelled to internet fame after clips of her leading protest chants went viral, addresses protesters on April 10. Hide Caption 33 of 43 Photos: In pictures: Sudan in transition Sudanese soldiers transport a body near the military headquarters on Tuesday, April 9. The Central Committee of Sudan Doctors said 22 people, including five soldiers, had been killed in mass protests. Hide Caption 34 of 43 Photos: In pictures: Sudan in transition A person writes "Down with Bashir" during an April 9 demonstration in Khartoum. Hide Caption 35 of 43 Photos: In pictures: Sudan in transition People protest on April 8, in front of the military headquarters in Khartoum. Hide Caption 36 of 43 Photos: In pictures: Sudan in transition A protester shows bullet cartridges during an April 8 demonstration. Hide Caption 37 of 43 Photos: In pictures: Sudan in transition Protesters sit atop a military vehicle as soldiers stand nearby on April 7. Hide Caption 38 of 43 Photos: In pictures: Sudan in transition Protesters run for cover on April 6, as tear-gas canisters are fired by police. Hide Caption 39 of 43 Photos: In pictures: Sudan in transition A protester retreats from tear gas during an anti-government demonstration on February 24. Hide Caption 40 of 43 Photos: In pictures: Sudan in transition A protester carries a Bashir portrait on February 8. It reads, "Down and that is all." Hide Caption 41 of 43 Photos: In pictures: Sudan in transition People take part in an anti-government demonstration in Omdurman, Sudan, on January 29. Hide Caption 42 of 43 Photos: In pictures: Sudan in transition A protester is seen in the midst of tear gas during clashes with security forces in Khartoum in December 2018. Hide Caption 43 of 43

The Declaration of Freedom and Change announced a general strike and civil disobedience.

It called on "honorable" members of various security forces to protect the people from the "militias of the putschist council" and to support a civilian transitional authority. They also called on the international community "not to recognize the military coup and to side with the Sudanese revolution."

Continued protests since Bashir forced out of power

In April, Sudan's former leader Bashir was arrested and forced out of power in a military coup after the country became engulfed in protests opposing his three-decade rule.

Irfan Siddiq, the British ambassador in Khartoum, called for an end to the violence.

"Extremely concerned by the heavy gunfire I've been hearing over the last hour from my residence and reports that Sudanese security forces are attacking the protest sit-in site resulting in casualties," he said on Twitter. "No excuse for any such attack."

An interim military council said it would lead the country through a transition period of up to two years, but protesters vowed to remain in the streets until a return to civilian government was guaranteed.