(CNN) A United Nations resolution calling for a 30-day ceasefire in Syria appears "to be ink on paper," according to doctors working inside the besieged Damascus suburb of Eastern Ghouta, which suffered intense bombardment again Sunday.

"Nothing has changed," Dr. Hamza Hassan said Sunday morning from Arbeen Hospital in Eastern Ghouta, hours after the UN unanimously adopted the resolution.

"The airstrikes are continuing. A maternity hospital has just been hit in Saqba (a town in Eastern Ghouta) and is out of service," he said of the offensive from the Russian-backed Syrian regime on the rebel-held enclave.

At least seven people are believed to have been killed since the resolution was passed, UN Humanitarian coordinator Panos Moumtzis told CNN on Sunday.

The airstrikes and artillery fire have concentrated on the outskirts of Eastern Ghouta, according to activists inside the city. Sunday's hostilities also included ground attacks for the first time in this offensive, they said.

More than 520 people have been killed and 2,500 wounded since the relentless bombardment of Eastern Ghouta began last Sunday.

A wounded girl is carried in Douma, Eastern Ghouta.

The Syrian regime says it is targeting terrorists inside the enclave.

Meanwhile, rebel groups in the area fired mortars into Damascus last week, causing dozens of deaths and injuries, Syrian state-run media SANA reported.

Pope Francis also weighed in on Sunday, calling for an immediate cessation to the violence. He told a crowd of 15,000 gathered in St Peter's Square in Rome that the situation in Syria had "re-exploded" recently.

Who has agreed to the ceasefire?

A ceasefire in Eastern Ghouta would allow for the delivery of much-needed medical supplies and evacuation of the wounded.

But after the ceasefire vote, Syrian UN Ambassador Bashar Ja'afari said the regime would continue to go after what it deemed terrorist groups.

"We practice a sovereign right of self-defense, and we will continue to fight terrorism wherever it is found on Syrian soil," he said, according to SANA.

Russia, a key ally of Syria, was accused by the United States of using its position on the UN Security Council to stall ceasefire talks, before eventually agreeing to the resolution Saturday.

Moscow has sought to lay the blame for the crisis on the rebel groups, saying they have derailed talks to resolve the conflict and are preventing civilians from leaving the enclave.

Likewise, Iran, also an ally of Syrian President Bashar al-Assad's regime, sees the area as under "terrorist" control and therefore not subject to the ceasefire.

"Parts of the Syrian outskirts that are under the control of terrorists are not under the ceasefire, and clearing operations will continue there," said Mohammad Bagheri, chief of staff of the Iranian Armed Forces, speaking at a defense gathering in Tehran Sunday, according to the semi-official Tasnim news agency.

Is this the next Aleppo?

As the death toll soars, analysts have raised fears the rebel-held enclave could face a similar fate to eastern Aleppo, which was all but destroyed in a government offensive in December 2016.

"It is highly frustrating that the resolution was adopted but we haven't seen a cessation in hostilities," said Moumtzis, the UN official, on Sunday.

"We hope it will not be another Aleppo, with entire parts of the city destroyed."

Photos: Airstrikes in Eastern Ghouta Medics tend to a baby as a child cries next to them at a makeshift clinic in Douma, Syria, on Thursday, February 23. More than 400 civilians have been killed this week in Syria's rebel-held Eastern Ghouta region, according to the head of the region's health department on Friday, February 23. Syrian regime forces have been pounding Eastern Ghouta with shells, mortars and bombs. Hide Caption 1 of 15 Photos: Airstrikes in Eastern Ghouta A man rescues a child after a reported airstrike in the rebel-held town of Hamouria on Wednesday, February 21. Syria says it is targeting terrorists in Eastern Ghouta. Hide Caption 2 of 15 Photos: Airstrikes in Eastern Ghouta Members of a Syrian civil-defense team rescue a man in Hamouria on February 21. Hide Caption 3 of 15 Photos: Airstrikes in Eastern Ghouta A woman and children run for cover after bombing in Hamouria on Monday, February 19. Hide Caption 4 of 15 Photos: Airstrikes in Eastern Ghouta Hide Caption 5 of 15 Photos: Airstrikes in Eastern Ghouta An injured child cries as he receives treatment at a makeshift hospital in Hamouria on February 19. Hide Caption 6 of 15 Photos: Airstrikes in Eastern Ghouta A man carries an injured victim amid the rubble of buildings. Hide Caption 7 of 15 Photos: Airstrikes in Eastern Ghouta A boy waits to receive medical treatment at a field hospital on February 19. Hide Caption 8 of 15 Photos: Airstrikes in Eastern Ghouta Injured children are treated at a hospital in Douma. Hide Caption 9 of 15 Photos: Airstrikes in Eastern Ghouta A wounded boy receives treatment in Douma following airstrikes on the village of Mesraba. Hide Caption 10 of 15 Photos: Airstrikes in Eastern Ghouta A man carries an infant he rescued from the rubble in Hamouria on February 19. Hide Caption 11 of 15 Photos: Airstrikes in Eastern Ghouta Injured children are treated at a hospital in Douma. Hide Caption 12 of 15 Photos: Airstrikes in Eastern Ghouta Ghaith, a wounded 12-year-old boy, cries as he waits for treatment -- and news of his mother in the operating room -- at a makeshift hospital in Kafr Batna. They were hurt in airstrikes on the town of Jisreen. Hide Caption 13 of 15 Photos: Airstrikes in Eastern Ghouta Children cry at a makeshift hospital in Douma. Hide Caption 14 of 15 Photos: Airstrikes in Eastern Ghouta A man weeps over his child, who was killed in the Mesraba airstrikes. Hide Caption 15 of 15

And Dr. Hassan expressed concern the ceasefire agreement would fail to translate to real action on the ground.

Smoke billows following Syrian government bombardments on Kafr Batna, in the besieged region of Eastern Ghouta.

"The people are waiting for translating the ceasefire and its content to actual implementation on the ground that will stop the killing and bring in humanitarian goods to Eastern Ghouta," he said.

"Enough bloodshed. There is not one person in a Syria who hasn't lost a family member, or dear person, or a friend. Everyone has been affected by this civil war in the past seven years."

The main rebel units holding territory in Eastern Ghouta are Islamist groups Jaish Al Islam and Faylaq Al Rahman, who have taken part in negotiations in the past, along with small pockets of Hayat Tahrir Al Sham, a former al Qaeda affiliate, according to activists.