Washington is pressuring Prime Minister Benjamin Netanyahu to accede to its proposal to resume Israeli-Palestinian peace talks on the basis of U.S. President Barack Obama's May 19 speech.

An Israeli source who spoke recently with senior officials in Washington said the Americans were very frustrated with Netanyahu's behavior, feeling that he was impeding America's efforts to keep the Palestinians from unilaterally seeking UN recognition of a state in September.

Netanyahu's personal envoy, Isaac Molho, spent last week in Washington, where the Americans presented their proposal for resuming talks on the basis of Obama's speech. Specifically, Obama's plan calls for negotiating over borders and security first, while deferring issues such as Jerusalem and the refugees until later. It also calls for the borders to be based on the 1967 lines, with mutually agreed land swaps.

The Americans told Molho that to block European initiatives such as France's proposal for an international peace conference in Paris, they must have something concrete to offer, like Netanyahu's agreement to negotiate on the basis of Obama's speech.

The U.S. proposal was also given to chief Palestinian negotiator Saeb Erekat, who said the Palestinians would resume talks on this basis.

Meanwhile, a European diplomat who was briefed on Molho's talks in Washington said they were fruitless. "The Americans didn't get anything new from Molho," the diplomat said.

This week, American diplomat David Hale will arrive in Israel to hold further meetings with both Molho and Erekat. Hale is temporarily replacing George Mitchell, the U.S. special envoy who resigned earlier this year.

An Israeli source who maintains close ties with both senior U.S. officials and people close to Netanyahu said that Washington's frustration began with Netanyahu's trip to Washington last month, when he publicly fought with Obama and then refused in an address to Congress to endorse the president's outline for talks. The Americans were now speaking very harshly of Netanyahu, said the source.

"He's asking us to protect him in September, but he isn't giving us any tools with which to help him," the source quoted one American official as saying. "Instead of helping us, he's making it harder for us."

As a result, American officials complained, Obama was unable to get Britain and France to commit to opposing a unilateral Palestinian move when he visited Europe last month.

"The Americans need Israel inside, but Netanyahu isn't there yet," the source said. "To date, from the American and European perspective, Israel hasn't given anything."

European diplomats said Netanyahu's speech to Congress was viewed in Europe as one long "no" and had thus increased European distrust of him. "We want to hear Netanyahu say he's willing to negotiate on the basis of Obama's speech and that he'll discuss borders based on the 1967 lines with land swaps," said one diplomat.

Since the barren talks with Molho last week, the White House has been upping the pressure on Netanyahu. On Friday, Steve Simon, who heads the U.S. National Security Council's Middle East desk, told American Jewish leaders that Netanyahu needs to reply within a month to the U.S. proposal for restarting talks. The White House knew this remark would both be conveyed to Netanyahu and leaked to the American and Israeli press, thus making its displeasure public.

But Netanyahu's office insisted it was "unaware of any American pressure or ultimatum."

Yesterday, Netanyahu flew to Italy, where he will meet with Prime Minister Silvio Berlusconi today. The latter has already announced that Italy will oppose any unilateral Palestinian move.

On Tuesday, German Foreign Minister Guido Westerwelle will meet with Netanyahu to warn that while Berlin also opposes unilateral statehood, if the diplomatic impasse continues, it will sponsor a UN Security Council resolution, together with Britain and France, that calls on the council to endorse Obama's speech as the basis for talks.