US House of Representatives Speaker John Boehner has invited Israeli Prime Minister Benjamin Netanyahu to address the US Congress on Iran without consulting President Barack Obama, and the White House questioned whether protocol had been violated.

Setting up a diplomatic showdown on an issue that has sharply divided Obama and congressional Republicans, Boehner announced the invitation on Wednesday, the day after Obama pledged in his State of the Union address to veto Iran sanctions legislation being developed in congress.

An Israeli official said that Netanyahu, whose relationship with Obama has often been tense, was looking into the possibility of meeting with Obama when he comes to Washington to address a joint session of Congress on February 11.

White House spokesman Josh Earnest said: "The protocol would suggest that the leader of one country would contact the leader of another country when he's travelling there. This particular event seems to be a departure from that protocol."

Asked by a reporter if inviting Netanyahu without speaking to the White House was a "poke in the eye" to Obama, Boehner, a Republican, said: "The Congress can make this decision on its own. I don't believe I'm poking anyone in the eye."

Lawmakers trying to amass enough support to override any veto by Obama, are developing several pieces of Iran-related
legislation, including a bill to tighten sanctions if a final nuclear agreement is not reached before the end of June.

On Wednesday, the US Senate Foreign Relations Committee held a contentious hearing on Iran with administration officials. The Senate Banking Committee is due to vote on the sanctions bill next week.

Speaking to reporters travelling with Obama aboard Air Force One, Earnest said the White House was reserving judgement until there was a chance to discuss Netanyahu's trip with Israeli officials.

"We'll need to hear from them about what their plans are and what he plans to say in his remarks to Congress before we have a decision to make about any meeting," Earnest said.

Separately, the US State Department said US and Iranian negotiators would hold talks in Switzerland on Friday and Saturday about Iran's nuclear programme.

Source: Agencies