Robert Gates, the US defence secretary, on Friday dismissed concerns that the Pentagon would send US troops across the Iraqi border into Iran to disrupt networks allegedly supplying weapons to Shia militias in Iraq.

President George W. Bush this week raised alarm that the US might be considering military operations against Iran. In his speech to the nation announcing the surge in US troops in Iraq, Mr Bush accused Iran of providing material support for attacks on US forces in Iraq.

But Mr Gates on Friday said the US planned only to disrupt Iranian activities within Iraq.

"It refers strictly to operations inside the territory of Iraq, not crossing the border," Mr Gates said in his first appearance as Pentagon chief before the Senate armed services committee.

General Peter Pace, the chairman of the Joint Chiefs of Staff, added that "from a military standpoint, [there was] no need to cross the Iranian border". US forces this week apprehended five Iranian nationals in a raid on an Iranian liaison office near Irbil in northern Iraq.

Mr Gates and Gen Pace faced a less hostile reception than Condoleezza Rice, secretary of state, received before the Senate foreign relations committee on Thursday when she was lambasted her over administration's plan to send an extra 21,500 US troops to Iraq. But most Democrats, and some Republicans, on the armed services committee strongly questioned whether Nouri al-Maliki, Iraqi prime minister, would live up to his commitments to send more Iraqi troops into Baghdad.

Democrats have argued that there is little evidence that Mr Maliki is willing to crack down on Shia militias. Bush administration officials have argued that he is 100 per cent supportive of the plan, which they say he developed. But Susan Collins, a moderate Maine Republican, asked Mr Gates what had changed since Mr Maliki told her three weeks ago that he did not want more US troops in Iraq.

Mr Gates responded: "There is no question in my mind that Prime Minister Maliki wanted to do this operation on his own."

"I think what happened is that as his own military and security leaders began looking at the operation and began working out the details and then began talking and consulting with General Casey and the American military planners, that they essentially persuaded the prime minister that additional American forces were necessary in order to make his plan successful."

When asked whether he believed Mr Maliki was completely supportive of the plan to pacify Baghdad, Gen Pace would only say that he believed the "Iraqi leadership is 'saying' they are 100 per cent on board".

Carl Levin, the Democrat chairman of the committee, asked Mr Gates why the American public should have any faith that Mr Maliki would fulfil his pledges to the US when he had repeatedly failed to do so in the past.

Copyright The Financial Times Limited 2007

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