Washington: The administration of President Barack Obama has deployed unmanned Predator drones in Yemen to hunt for Al Qaida operatives who are becoming increasingly active in that Arab country, The Washington Post reported Sunday.

But citing unnamed senior US officials, the newspaper said US military and intelligence operatives have not fired missiles from these aircraft because they lack solid intelligence on the militants' whereabouts.

Last month, two packages addressed to synagogues in Chicago containing the hard-to-detect explosive PETN hidden in printer ink cartridges were uncovered in Dubai and Britain's East Midlands Airport, sparking a global scare.

On Friday, the Yemeni branch of Al Qaida claimed responsibility for the plot and for the September downing of a UPS cargo plane.

The Al Qaida in the Arabian Peninsula (AQAP) group posted the message on "jihadist" web forums, and called for more explosive parcels to "enlarge the circle of its application to include civilian aircraft in the West as well as cargo aircraft."

US officials said the Predators have been patrolling the skies over Yemen for several months in search of leaders and operatives of Al Qaida, the report said.

But after a series of attacks by Yemeni forces and US cruise missiles earlier this year, Yemeni Al Qaida leaders "went to ground," The Post quotes a senior Obama administration official as saying.

Yemeni officials said they had deep reservations about weapons they said could prove counterproductive, the paper noted.

"Why gain enemies right now?" The Post quotes Mohammad Abdul Ahoum, a senior Yemeni official, as saying. "Americans are not rejected in Yemen; the West is respected. Why waste all this for one or two strikes when you don't know who you're striking?"

Instead, Yemen has asked the United States to speed up shipment of promised helicopters and other military equipment, the report said.

A US defence official said plans were being made to nearly double military aid, to $250 million, in 2011, The Post noted.

US Defence Secretary Robert Gates said in Australia Saturday that the US military was looking at how to bolster Yemen's security forces amid growing concern over Al Qaida's foothold in the country.

"I think in terms of training and so on there are things that we can do to help the Yemenis and strengthen their capabilities," Gates told reporters on his plane before flying in to Melbourne.