The United States yesterday upped pressure on the interim leaders of Honduras, as ousted President Manuel Zelaya remained defiant in Nicaragua one month after the army sent him away.

The US is currently reviewing the diplomatic visas for a number of interim government members and "has revoked visas to four such individuals", State Department spokesman Ian Kelly told reporters in Washington.

"We don't recognise Roberto Micheletti as the president of Honduras," he added when asked why Washington took the measure.

But Mr Kelly rejected the notion that the revocation of visas amounted to ratchetting up pressure on the interim leadership.

"I don't think I would characterize it that way," the spokesman said. "But what we are doing is we're trying to do everything that we can to support this... process that was begun by Costa Rican President (Oscar) Arias and the negotiation efforts.

Rather, he said, the move was "consistent with our policy of the non-recognition of the de facto regime."

Mr Zelaya has said the Costa Rica talks have failed and ruled out further negotiations.

The Honduran Congress on Monday set up a commission to study the peace accord proposed by Mr Arias, which calls for Mr Zelaya to be restored to power, but with various limits.

The interim leaders have welcomed parts of the Arias plan but rejected Mr Zelaya's return as president, as has the military.

After international condemnation, aid freezes and stalled peace talks, Mr Zelaya said from exile in Nicaragua that the military coup on June 28, which was backed by the Honduran courts and Congress, had failed.