SANAA (AFP) – Deadly fighting between Yemeni troops and suspected Al-Qaeda gunmen raged in south Yemen Tuesday, as the United States pressed wounded President Ali Abdullah Saleh to hand over power.

At least 15 people were killed, nine of them soldiers, in clashes which erupted when troops during the night advanced on the city of Zinjibar in a bid to wrest it back from the control of extremists, the military and medics said.

Residents reported sporadic fighting outside Zinjibar on Tuesday, saying the army had not yet managed to enter the city.

Suspected Al-Qaeda militants have controlled much of Zinjibar, capital of Abyan province, since they overran it on May 29. Only the military base inside the city, home to the 25th mechanised brigade, remains in government hands.

“Heavy fighting broke out between the army and Al-Qaeda gunmen when troops advanced towards the city to storm it,” said a military official, giving a toll of nine soldiers dead and at least 10 wounded.

One medic confirmed the toll of soldiers while another said that a hospital in the nearby town of Jaar “received the bodies of six Al-Qaeda gunmen while four wounded militants were also brought in.”

The two sides blasted each other with machine guns, artillery rounds and mortar shells, military sources said, adding that the army would continue fighting the jihadists until the city is freed from their grip.

Military commanders told AFP Monday that three brigades had been brought to Zinjibar from the provinces of Aden and Lahij.

Security officials insist the militants holding the city are Al-Qaeda fighters but the political opposition accuses the government of embattled Saleh of inventing a jihadist threat in a bid to head off Western pressure on his 33-year rule.

Saleh, 69, is recuperating in a Saudi hospital after he was wounded in an attack on his palace last Friday.

The opposition, backed by and young protesters, has vowed to prevent his return to power while the United States urged an “immediate transition.”

But Saleh’s deputy Abdrabuh Mansur Hadi said the president’s health was quickly improving and that he would return to Yemen within days ready again to take the helm of his regime, which after four months of deadly unrest is teetering.

Washington urged Saleh to step down immediately.

“We believe that an immediate transition is in the best interests of the people and the best interest of maintaining stability in obviously a very unstable situation,” said White House spokesman Jay Carney.

US Secretary of State Hillary Clinton, speaking alongside French counterpart Alain Juppe at a Washington press conference, made it clear Saleh should leave power but stopped short of expressly ordering him to do so.

“Obviously, I can’t speculate on what President Saleh is going to do or say, but we do want to emphasise we’re calling for a peaceful and orderly transition, a non-violent transition that is consistent with Yemen’s own constitution,” she said.

“We think an immediate transition is in the best interest of the Yemeni people, because the instability and lack of security currently afflicting Yemen cannot be addressed until there is some process that everyone knows is going to lead to the sort of economic and political reforms that they are seeking.”

Washington supports a deal, brokered by the regional Gulf Cooperation Council bloc, that would see Saleh cede power to an interim administration within 30 days, in exchange for immunity from prosecution.

Saleh, a wily operator who since 1978 has bought off tribal loyalties and stitched them together into a governable framework, has refused to sign the accord and warned that his ouster would only serve to boost Al-Qaeda.

Hours after Friday’s attack on Saleh, State Department official Shari Villarosa said: “While we are in a period of uncertainty, I’d stress that our shared interest with the Yemeni government in fighting terrorism, particularly defeating Al-Qaeda in the Arabian Peninsula, does not rely solely on one individual.

“We are hopeful that any future Yemeni leaders will be solid counter-terrorism partners,” said Villarosa, the deputy counterterrorism coordinator for regional affairs.

Yemen is the home of Al-Qaeda in the Arabian Peninsula, an affiliate of the slain Osama bin Laden’s militant network. The group is blamed for anti-US plots including trying to blow up a US-bound airplane on Christmas Day in 2009.