WASHINGTON – The Pentagon said Tuesday there were no plans to suspend US military assistance to Yemen but urged a swift transition of power amid a wave of anti-regime protests.

Asked at a news conference if the US administration was considering withholding military aid due to unrest and violence against demonstrators, press secretary Geoff Morrell said: "As far as I know, it has not been (considered)."

"Obviously, we are monitoring the situation closely. It's fluid," Morrell said.

Tensions are running high in Yemen after 24 people were killed in anti-regime unrest, with European governments condemning violence by President Ali Abdullah Saleh's regime.

Washington had viewed the autocratic leader, in power since 1978, as a valuable ally in its fight against Al-Qaeda in the region but the United States shifted its stance this week, urging Saleh to peacefully relinquish power.

"The situation right now is a difficult one, the longer it festers the more difficult it becomes," Morrell told reporters.

"That is why this government has been urging a negotiated transition as quickly as possible."

He said the threat from Al-Qaeda in Yemen was serious and suggested US military assistance would continue no matter the outcome of the political turmoil.

Once there is a political settlement, "we will be able to better collectively go after this threat that exists in Yemen," he said.

In 2010, the Defense Department spent $150 million to train and arm Yemen?s security forces and has requested from Congress more than $100 million for the current fiscal year and $115.6 million in military and economic aid for 2012.

Morrell said there was no evidence to show that weapons supplied by the United States had been used by the regime against demonstrators.

The White House on Monday expressed fears that Al-Qaeda's affiliate in the country could take advantage of a power vacuum produced by the upheaval.

Western officials believe Al-Qaeda's branch in Yemen was behind a failed plot to blow up an airliner bound for Detroit in 2009 and an attempt to detonate explosives last year on a cargo plane bound for Chicago.

In Yemen, Saleh's official response to opposition demands to step down and hand over to his deputy for an interim period has been to urge protesters to dismantle their roadblocks and go home.

Saleh has said he is willing to step down by the end of this year, but his ruling General People's Congress party has defiantly said he should serve out his term until 2013.