Israel's prime minister pledged Sunday to resist "pressures" as he left for Washington on a visit expected to centre on peace talks with the Palestinians and the Iranian nuclear dispute.

"I am now leaving on an important trip to the US where I will meet with President Barack Obama," Prime Minister Benjamin Netanyahu's office quoted him as saying as he boarded his plane.

"We will discuss the Iranian issue and the diplomatic process... In recent years the state of Israel has been under various pressures. We have rejected them...This is what has been and what will be."

Although Netanyahu would like the talks with Obama on Monday to focus on Iran's nuclear ambitions, the White House appears to have a different agenda.

The New York Times, citing senior US officials, reported earlier this week that Obama would press Netanyahu to agree on a framework for a conclusive round of peace talks with the Palestinians that is being drafted by Secretary of State John Kerry.

But top-selling Israeli daily Yediot Aharonot said the worsening crisis in the Ukraine might have changed the White House's plans.

"Contrary to reports that President Obama intends to engage directly in the negotiations, it seems that he is too busy with the crisis in Ukraine for that, and ...does not anticipate that such an effort...has a very high chances of success," it wrote.

Direct peace talks between Israelis and Palestinians, which began last July with the goal of reaching a deal within nine months, have made no visible progress.

Kerry is now focused on getting the two sides to agree on a framework proposal which would extend the deadline until the year's end.

Although the document has not yet been made public, it is understood to be a non-binding proposal laying out guidelines for negotiating the central issues of the conflict, such as borders, security, Jerusalem, Israeli settlements and the fate of Palestinian refugees.

The proposal, or its outline, is likely to be presented to Netanyahu next week and to Palestinian president Mahmud Abbas on March 17 when he meets Obama at the White House.

The aim is reportedly to secure an agreement before the end of March, when Israel is due to release a fourth and final batch of 26 veteran Palestinian security prisoners in line with commitments to Washington.

Left-leaning Israeli daily Haaretz, citing Israeli officials who met counterparts in Washington on Friday, said they "sensed pessimism regarding the possibility of reaching an framework agreement by the end of March."

While Kerry faces an uphill battle to win over a Palestinian leadership which has steadfastly refused any extension, following months of relentless Israeli settlement expansion, pundits said the prime minister was likely to agree, albeit with reservations.

"This is a crucial meeting with Obama, which is going to determine the shape of the framework for further negotiations," said Eytan Gilboa, an expert on US-Israeli relations at Bar Ilan University.

"What both Kerry and Obama are hoping to get is some kind of approval from Netanyahu for the document," he told AFP, saying the Israeli leader was likely to accept the framework rather than risk being blamed for the collapse of the talks.

- 'Change of script' -

Netanyahu is likely to reprise his criticism of an interim agreement reached between world powers and Iran in November under which Tehran agreed to freeze or curb its controversial nuclear activities in exchange for sanctions relief.

But Haaretz analyst Chemi Shalev said Russia's threatened intervention in Ukraine "changes the script" for Netanyahu, who will also meet with congressional leaders and deliver an address Tuesday to the annual conference of the powerful pro-Israel lobby AIPAC.

"Netanyahu will have a harder time diverting anyone's attention to Iran or convincing American public opinion that Iran is the greatest danger facing the United States," he wrote.

"It is Putin who is now cast as the ultimate bad guy for America, while Iran's (President) Hassan Rouhani - who continued his charm offensive on Saturday by disavowing nuclear weapons and reprimanding Iranian generals for their bellicosity - isn't even a distant second."