A rift appeared to open between Britain and the US last night over the control of coalition troops in post-handover Iraq.

Tony Blair told journalists at his monthly press conference in Downing Street that the new Iraqi government would have a veto over military activities after June 30.

"The final political control remains with the Iraqi government. That is what the transfer of sovereignty means," the prime minister said.

"That doesn't mean to say that our troops are going to be ordered to do something our troops don't want to do. That remains as it is now.

"But the transfer of sovereignty has to be real and genuine, and the issue of our troops remaining after then is an issue of necessity because they have to remain until the Iraqi capability is sufficiently developed."

But speaking later in Washington secretary of state Colin Powell insisted that "US forces remain under US command and will do what is necessary to protect themselves".

Both sides deny a dispute but today's press concludes that the two positions appear difficult to reconcile.