KABUL: Three local staffers for Doctors Without Borders were killed and 30 were missing after an explosion near their hospital in the northern Afghan city of Kunduz that may have been caused by a US airstrike. In a statement, the international charity said the 'sustained bombing' took place at 2:10 a.m. (2140 GMT). Afghan forces backed by US airstrikes have been fighting to dislodge Taliban insurgents who overran Kunduz on Monday. US forces in Afghanistan said they conducted an airstrike on Kunduz at 2:15 a.m. The spokesman, US Army Col. Brian Tribus, said the strike 'may have resulted in collateral damage to a nearby medical facility' and that the incident was under investigation. Tribus said it was the 12th US airstrike 'in the Kunduz vicinity' since Tuesday. Doctors Without Borders said its trauma center 'was hit several times during sustained bombing and was very badly damaged.' At the time of the bombing, the hospital had 105 patients and their care-takers, and more than 80 international and Afghan staff, it said. The group said all of its international staffers were alive and accounted for. Adil Akbar, a doctor at the trauma center who was on duty at the time, told The Associated Press that the operating theater, emergency room and other parts of the hospital complex had been hit in the bombing. 'I managed to escape after the attack but I know that most of the staff and even some of the patients are missing,' he said. Zabihullah Pashtoonyar, a former local radio reporter who was working as a security guard at the compound, was one of those killed in the incident, said his relative Gul Rahim. The number of dead and missing was provided by the charity. Sarwar Hussaini, the spokesman for the Kunduz provincial police chief, could not immediately confirm the number of casualties. Wahidullah Mayar, spokesman for the Public Health Ministry, tweeted that 37 people were wounded, among them 24 medical and non-medical staff. Bart Janssens, the charity's director of operations, said 'we do not yet have the final casualty figures,' adding that the group's medical team was treating wounded patients and staffers. Doctors Without Borders said it had treated 394 people wounded in fighting since the Taliban attacked the city. Afghan forces went in on Thursday, and the fighting has been underway since then as government troops try to clear the city of insurgents. Taliban spokesman Zabihullah Mujahid issued a statement saying there were no Taliban fighters in the hospital at the time of the bombing. It accused Afghanistan's intelligence service of misdirecting the airstrike to purposefully hit the hospital. The clinic in Kunduz is a sprawling facility with numerous buildings situated in the east of the city, in a residential area close to the local office of the NDS intelligence service. Another Kunduz resident, Dawood Khan, said a cousin who works at the clinic as a doctor was lightly wounded in the bombing incident. 'I heard the sound of the bomb and rushed to the hospital to get news. The operating theater was on fire, people were terrified, running everywhere,' he said. Electricity and water have been cut off since the Taliban's Monday assault and seizure of the city, officials and residents said. Food and medical supplies cannot get through because the Afghan military is still working to clear mines planted by the Taliban. Sporadic gunfights are continuing in various pockets of the city, as troops advance street by street. Most of the Talban appear to have fled the city after the troops moved in on Thursday, taking looted vehicles, weapons and ammunition with them. Officials have reported that they have moved east, into Takhar and Badakhshan provinces, where a number of districts fell to Taliban control on Friday. The Defense Ministry said troops had retaken the Baharak district after retreating under fire Friday. The US Embassy in Kabul issued an emergency notice to Americans in Badakhshan, saying they should 'consider departing the area immediately.'