At least 30 soldiers have been killed in a huge Taliban attack on a national security base, Afghan officials have said.

The militants have said that three US Marines were killed in the assault in the early hours of Wednesday, although the claim has not been verified by the authorities.

The attack on an outpost in Kakhrez in Kandahar province - the heartland of the extremist insurgency - left another 13 soldiers wounded, defence ministry deputy spokesperson Mohammed Radmanish said.

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Militants reportedly managed to capture weapons and vehicles from the base during the swift assault, although 205th Corps Commander General Imam Nazar said that reinforcements managed to beat the attackers back.

There has been intense fighting in the region in recent days amid a renewed Taliban offensive which has also seen a string of horrific suicide attacks on civilians.

A Taliban spokesperson said on Wednesday that the insurgents had made strategically important gains across the country's south over the last week. The group is now in control of some 40 per cent of the country, although it has not managed to maintain a grip on any urban centres.

While Afghanistan's police and military forces total almost 300,000 personnel, they have struggled to contain the Taliban insurgency since the majority of US and international troops withdrew from the country in 2014.

Afghanistan: Between Hope and Fear Show all 16 1 /16 Afghanistan: Between Hope and Fear Afghanistan: Between Hope and Fear 2001 Afghans at the Killi Faizo refugee camp desperately reach for bags of rice being handed out to the thousands who escaped the bombardment in southern Afghanistan during Operation Enduring Freedom. (Chaman, Pakistan, December 4, 2001) Paula Bronstein Afghanistan: Between Hope and Fear 2002 Mahbooba stands against a bullet-ridden wall, waiting to be seen at a medical clinic. The seven-year-old girl suffers from leishmaniasis, a parasitical infection. (Kabul, March 1, 2002) All photos Paula Bronstein Afghanistan: Between Hope and Fear 2003 A mother and her two children look out from their cave dwelling. Many families who, fleeing the Taliban, took refuge inside caves adjacent to Bamiyan’s destroyed ancient Buddha statues now have nowhere else to live. (Bamiyan, November 19, 2003) Paula Bronstein Afghanistan: Between Hope and Fear 2007 Students recite prayers in a makeshift outdoor classroom in the Wakhan Corridor, a mountainous region in northeastern Afghanistan that extends to China and separates Tajikistan from India and Pakistan. (Northeastern Afghanistan, September 2, 2007) Paula Bronstein Afghanistan: Between Hope and Fear 2007 Bodybuilders in the 55-60 kg category square off during a regional bodybuilding competition. Many Afghan men, like others around the world, feel that a macho image of physical strength is important. (Kabul, August 6, 2007) Paula Bronstein Afghanistan: Between Hope and Fear 2008 A woman in a white burqa enjoys an afternoon with her family feeding the white pigeons at the Blue Mosque. (Mazar-e-Sharif, March 8, 2008) Paula Bronstein Afghanistan: Between Hope and Fear 2009 Addicts inject heroin while trying to keep warm inside the abandoned Russian Cultural Center, which the capital city’s addicts use as a common gathering point. Heroin is readily available, costing about one dollar a hit. (Kabul, February 9, 2009) Paula Bronstein Afghanistan: Between Hope and Fear 2009 An elderly man holds his granddaughter in their tent at a refugee camp after they were forced to flee their village, which US and NATO forces had bombed because, they claimed, it was a Taliban hideout. (Surobi, Nangarhar Province, February 7, 2009) Paula Bronstein Afghanistan: Between Hope and Fear 2009 Seven-year-old Attiullah, a patient at Mirwais Hospital, stands alongside an X ray showing the bullet that entered his back, nearly killing him. Attiullah was shot by US forces when he was caught in a crossfire as he was herding sheep. (Kandahar, October 13, 2009). Paula Bronstein Afghanistan: Between Hope and Fear 2010 US Army Sargeant Jay Kenney (right), with Task Force Destiny, helps wounded Afghan National Army soldiers exit a Blackhawk helicopter after they have been rescued in an air mission. (Kandahar, December 12, 2010) Paula Bronstein Afghanistan: Between Hope and Fear 2010 An Afghan National Army battalion marches back to barracks at the Kabul Military Training Center. (Kabul, October 4, 2010) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Eid Muhammad, seventy, lives in a house with a view overlooking the hills of Kabul. He and millions of other Afghans occupy land and housing without possessing formal deeds to them. (Kabul, November 21, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Razima holds her two-year-old son, Malik, while waiting for medical attention at the Boost Hospital emergency room. (Lashkar Gah, Helmand Province, June 23, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Young women cheer as they attend a rally for the Afghan presidential candidate Ashraf Ghani. (Kabul, April 1, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Burqa-clad women wait to vote after a polling station runs out of ballots. (Kabul, April 5, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2015 Relatives, friends, and women’s rights activists grieve at the home of Farkhunda Malikzada, who was killed by a mob in the center of Kabul. Farkhunda was violently beaten and set on fire after a local cleric accused her of burning a Qur’an. (Kabul, March 22, 2015) Paula Bronstein

Civilian and military deaths have sky rocketed since, and the chaos has allowed Isis to gain a foothold in Afghanistan's remote east.

The unrelenting violence has led to widespread anger with the weak and divided government of President Ashraf Ghani, which they say is not doing enough to protect the people from militant violence.

A car bomb attack in capital Kabul this week killed at least 35 people, bringing the number of civilian dead so far in 2017 to 1,697.

A total of 6,800 Afghan soldiers were killed by hte Taliban and Isis in 2016, a figure the US Special Inspector General for Reconstruction (SIGAR) called "shockingly high".

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Last month US President Donald Trump bowed to pressure from the Pentagon to allow the military to set its own troop levels to prevent the precarious security situation from deteriorating further.

A total of 13,000 US and Nato soldiers are currently in the country, although observers fear after 16 years of war Afghanistan has arrived at a stalemate in the fight against extremism.