Obama will not meet US-bound Netanyahu

US President Barack Obama will not meet Israel's prime minister when he makes a controversial visit to the US in early March, the White House said Thursday. 

National Security Council spokeswoman Bernadette Meehan said it was a "matter of long-standing practice and principle" that the president not meet candidates or incumbent leaders while they are on the campaign trail.

The Israeli leader is up for re-election on 17 March, two weeks after his slated visit to Washington.

US Secretary of State John Kerry will also pass on meeting with Benjamin Netanyahu, according to a State Department spokesperson. 

Netanyahu has been invited to address a joint session of Congress, to speak about the threat from Iran - which is accused of building a nuclear weapon, a charge Tehran denies.

The topic causes heartburn for the White House, which along with European allies, is engaged in the final phase of talks with Iran to end a decade-long nuclear standoff.

Obama's allies fear the trip could be used by Israel and by the Republicans, who control Congress, to rally opposition to a grand bargain, undercutting talks just as they appear poised to bear fruit.

On Wednesday, the White House gave an icy response to news of Netanyahu's trip, branding it a a break with protocol.

Netanyahu - and his Congressional hosts - have expressed deep skepticism about a brokered deal, believing Iran cannot be trusted to keep its side of the bargain. 

US lawmakers have even sketched plans to increase sanctions on Iran, legislation Obama has said would wreck talks and which he would veto.

Netanyahu's visit looked set to consolidate that opposition, but the White House and its allies seem determined to push back. 

"The President has been clear about his opposition to Congress passing new legislation on Iran that could undermine our negotiations and divide the international community," said Meehan.

Four European foreign policy chiefs issued a joint call in support of Obama's position Thursday.

"Introducing new hurdles at this critical stage of the negotiations," they wrote in The Washington Post, "would jeopardize our efforts at a critical juncture."

Negotiators hope to have a framework deal in place by 31 March. 

The complex agreement would see Iran's nuclear program subjected to safeguards designed to ensure it remains useful only for power generation or non-military research.

While Israel and the United States remain close allies, Obama and Netanyahuhave publicly clashed of Iran and issues linked to the Middle East peace process.

In a Thursday statement, Netanyahu appeared to be trying to diminish the diplomatic damage caused by the controversy.

He said the speech would be an opportunity for him to "thank President Barack Obama, the Congress and the American people for their support of Israel".

The White House said Obama and Netanyahu had had many conversations on the issue of Iran. 

"I am sure they will continue to be in contact on this and other important matters," said Meehan.