WASHINGTON, Jan 27: US Defence Secretary Robert Gates said on Tuesday that the United States would continue drone strikes at suspected terrorist targets inside Fata and has conveyed its decision to the government of Pakistan.

Mr Gates told a US Senate panel that the Pentagon could send two more brigades to Afghanistan by late spring and a third by late summer. A US Army combat brigade typically comprises about 3,500 soldiers.

Mr Gates, who also served in the Bush administration as defence secretary, said that fighting Al Qaeda in its refuge inside Pakistan along the border with Afghanistan was an important objective also of the Obama administration.

The issue of US drone attacks in Fata was raised by the chairman of the Senate Armed Services Committee Carl Levin, who recalled that last week the Pakistan Foreign Ministry had issued a statement calling US missile strikes on Pakistani territory counter-productive and requested that they be discontinued.

“What’s your reaction to that?” Senator Levin asked.

“I think that the strikes that are being undertaken are -- well, let me just say both President Bush and President Obama have made clear that we will go after Al Qaeda wherever Al Qaeda is and we will continue to pursue them,” Secretary Gates said.

“Has that decision been transmitted to the Pakistan government?” Senator Levin asked. “Yes, sir,” said Mr Gates.

The secretary was testifying before the committee which oversees US defence efforts at home and abroad. It was his first hearing since President Obama took office and lawmakers were eager to hear details about how the new president planned to bolster operations in Afghanistan.

Mr Obama has indicated he wants to shift more military resources from Iraq to Afghanistan.

Secretary Gates told the panel that Afghanistan was America’s “greatest military challenge” and that more US troops were needed to improve security in dangerous areas of that country.

But he also acknowledged that there’s “no purely military solution”. Yet, the US has to send enough troops to “provide a baseline level of security” in some of the most dangerous areas.

Senator John McCain, the Arizona Republican who lost the presidency to Mr Obama, urged the new US administration to share its perception of the Afghan war with the people. “The American people must understand this is a hard, long slog we’re in, in Afghanistan,” he said.

Senator McCain said he did not see a “game-changing” strategy in Afghanistan similar to the “Anbar awakening” of Sunni Muslims in Iraq who rose up against insurgents with US backing.

Other lawmakers pointed out that the new administration and the new Congress were both facing contradictory budgetary pressures generated by a mounting federal deficit and the need to finance two wars.

Secretary Gates conceded that the US faced “hard choices” and that the war spending might hurt its programmes for developing new weapons.

“We may have to invest more in the future-oriented programme of one service and less in that of another, particularly when both programmes were conceived with the same threat in mind,” Mr Gates told the panel.

Senators McCain and Levin both said changes in the Pentagon’s acquisition of weapons would be a top priority for the committee.

Even as spending to ease the credit crisis and stimulate the economy has driven the deficit to more than $1 trillion, the US has about 177,000 troops deployed in Iraq and Afghanistan.

Secretary Gates said the Obama administration’s “highest priority” was to train and expand the Afghan army and police, which would give the US an “exit ticket” from the conflict.

While the troop build-up in Afghanistan is dependent on how quickly the administration draws down forces in Iraq, Mr Gates warned that the US could not expedite pullout from Iraq.