Post-Saleh Yemen would pose problem: US

Yemeni President Ali Abdullah Saleh's eventual fall or his replacement by a weaker leader would pose "a real problem" for US counter-terrorism work, Defense Secretary Robert Gates says.

In an interview with ABC television, Gates says Saleh's government and the Yemeni security services have helped the United States in fighting al-Qaeda's Yemeni branch.

"I think it is a real concern because the most active and, at this point, perhaps the most aggressive branch of al-Qaeda - al-Qaeda in the Arabian Peninsula - operates out of Yemen," Gates said on Sunday.

"And we've had counter-terrorism cooperation with President Saleh and the Yemeni security services," the defence secretary said.

"So if that government collapses, or is replaced by one that is dramatically more weak, then I think we'd face some additional challenges out of Yemen - there's no question about it. It's a real problem," he said.

The Washington Post said, according to US spy agencies, al-Qaeda in the Arabian Peninsula could be close to launching an attack as the group may be seeking to capitalise on unrest roiling the Arab country.

The rising threat comes as Saleh hangs on to power amid months of street protests and high-profile defections in the ranks of top military and tribal leaders just in the past two weeks. Saleh, in power for more than 30 years, has been a key US ally in its fight against the active al-Qaeda branch operating out of his country.

The group last year launched a failed plot to dispatch parcel bombs on US-bound cargo planes.

Alongside drone attacks targeting al-Qaeda, the United States over the last 18 months has also dispatched "dozens" of CIA operatives and even Special Operations military troops to operate alongside Yemeni forces to counter and disrupt the group's operations, the Post said.