WASHINGTON, Jan 24: The US State Department said on Monday that "skill ful and aggressive" efforts by Pakistani and American intelligence agencies have minimized Al Qaeda's influence in the region even if its leader Osama bin Laden is still at large.

The department's deputy spokesman Adam Ereli made these remarks while commenting on an observation that US efforts to capture Al Qaeda leaders have not been very fruitful because Osama and his key lieutenants were still free.

"There have been a number of important captures, both through the Rewards for Justice Programme and also through the aggressive and skillful work of Pakistani, American and other counter-terrorist officials and counter-terrorist forces," said Mr Ereli.

Under this programme the United States offers financial rewards to those who could lead US authorities to the suspects they want to capture. The programme led to the arrest of several wanted men in Iraq but has not been very effective against Al Qaeda leaders hiding in Afghanistan or Pakistan's tribal belt.

So far almost all senior Al Qaeda leaders in US custody were captured by Pakistanis and handed over to the Americans. Mr Ereli acknowledged that "several very important" Al Qaeda leaders were still free but many were either dead of jail. So, "the trend line is clearly in our favour," he said, adding that those still free were on the run.

Mr Ereli said the "benchmark" for assessing the success of the US reward programme was not to see how many Al Qaeda suspects were still at large but to "think in terms of what kind of constraint, what kind of difficulties having this reward out for you and being so much in the public eye presents for those who would do us harm."

He said the US Embassy in Islamabad and the Rewards for Justice Programme have launched a new ad campaign in Pakistan. The first ad that appeared on Jan. 7 featured photos and reward amounts for 14 terrorists who may be in the region, including Osama bin Laden, Mullah Omar and others.

There will be additional advertisements running in other Pakistani newspapers and airing on Pakistani radio and television stations in the next couple of weeks.

Asked if the US was going to double the $25 million reward for Osama, Mr. Ereli said that a law signed in December authorized the secretary of state to raise the reward offers up to $50 million but no decision had yet been made to do so.

"Obviously, as is always the case in the Rewards for Justice Programme, the amount of the reward is something that we keep under regular and consistent review to assess whether it's appropriate, whether it needs adjusting or not, and this case is no different," he said.