[Update 4 p.m.] Israel's delay in responding to a U.S. request to demonstrate its commitment to the peace process has contributed in part to a delay of proximity talks to be led by former Sen. George Mitchell, the Obama administration's special envoy to the Middle East.

Mitchell was originally scheduled to leave Sunday for talks in the region Tuesday, but his departure was postponed to await the Israeli response. State Department spokesman P.J. Crowley said Tuesday that due to "logistics" the trip will now take place after Mitchell participates in previously scheduled meetings Thursday and Friday in Moscow with the Mideast Quartet - four international entities seeking peace in the Middle East.

"There's simply not enough time to have meaningful discussions with the parties Wednesday in order to be in Moscow for the quartet meeting Thursday," he said.

Crowley did not give a specific date for the rescheduled talks.

[Posted 1:27 p.m. ] Secretary of State Hillary Clinton is dismissive of the view that relations between the United States and Israel are in crisis after a row between the two countries over settlements.

"Oh, I don't buy that," Clinton told reporters Tuesday at the State Department. "We have an absolute commitment to Israel's security. We have a close, unshakable bond between the United States and Israel and between the American and Israeli people."

An Israeli official earlier confirmed to CNN that Israel's ambassador to the United States, Michael Oren, had told his fellow Israeli diplomats that relations between the two countries were "in a crisis."

Clinton acknowledged the United States expressed its "dismay and disappointment" after Israel's announcement that it will allow construction of 1,600 settler housing units in East Jerusalem.

She said that U.S. and Israeli officials are in intense talks "over steps that we think would demonstrate the requisite commitment to this process," and the United States is waiting for a response from Israel on steps it is willing to take. She did not, however, say when or how that response would be conveyed.

"We'll see what the next days hold," she said. "There's just too much at stake for the Palestinians and the Israelis. ... Our goal now is to make sure that we have the full commitment from both our Palestinian and Israeli partners to this effort."