By Hamid Shalizi KABUL, Dec 9 (Reuters) - Afghan and NATO-led forces have captured two senior Taliban commanders during their offensive to retake the insurgents' most important stronghold in Afghanistan, the Afghan Defence Ministry said on Sunday. Musa Qala, in the southern province of Helmand, has a symbolic significance for both sides in the conflict in Afghanistan as the only sizeable Afghan town controlled by the Taliban. U.S. and British forces opened the operation on Friday, in the words of a British spokesman "kicking the door in to Musa Qala", to be followed up by an assault by Afghan forces. The operation is expected to last several days, but Afghan and foreign forces appeared to have scored an early victory with the capture of two top Taliban civilian commanders in Helmand. "During the operation, two Taliban commanders named Mullah Mateen Akhond and Mullah Rahim Akhond have been captured by joint forces," the Defence Ministry said in a statement. Mullah Rahim Akhond is the Taliban-appointed governor of Helmand, while Mullah Mateen Akhond is the Taliban dictrict governor of Musa Qala. The Afghan government appealed to Taliban fighters to lay down their arms. "The Taliban in Musa Qala must put their weapons down and surrender or they will face an offensive by Afghan forces," the Defence Ministry statement said. The NATO-led International Security Assistance Force (ISAF) does not release Taliban casualty figures, but the Afghan Defence Ministry said on Saturday 12 insurgents had been killed and two children also lost their lives, caught in the crossfire. Hundreds of civilians have fled the fighting. TALIBAN DUG IN One British soldier was killed in southern Afghanistan on Saturday, but it was not clear if the death was connected with the fighting. One foreign fighter was among the Taliban dead, the Afghan Defence Ministry said. A Taliban spokesman said insurgents had killed more than 30 NATO and Afghan troops and said four Taliban fighters had been killed. Qari Mohammad Yousuf said the insurgents were dug in to fortified bunkers in Musa Qala and warned of heavy casualties if NATO and Afghan troops attempted a final assault on the town. After coming under sustained Taliban attacks, British troops pulled out of Musa Qala in October last year in a truce criticised by U.S. commanders that handed control of the town to tribal elders. The Taliban then seized Musa Qala in February. U.S.-led and Afghan forces toppled the Taliban for refusing to give up al Qaeda leaders after the Sept. 11, 2001 attacks on the United States. But foreign forces had only a limited presence in Helmand, allowing the Taliban to regroup and take control of large parts of the mainly desert province until around 7,000 British troops moved in to the province around 18 months ago. Since then, there has been fierce fighting as British, Danish and Estonian ISAF troops and Afghan forces wrested control of the towns back from the Taliban. But the Taliban still control parts of the fertile Helmand River valley that runs through the desert and where nearly half the world's opium is grown. The insurgents carry out hit-and-run attacks and suicide bombs to weaken government control. The Taliban relaunched their insurgency two years ago with guerrilla attacks in the south and east and suicide bombings on cities across the country aimed at convincing Afghans their government and its Western allies cannot bring security. (Reporting by Hamid Shalizi; Writing by Jon Hemming; Editing by Alex Richardson)