WASHINGTON - US special envoy for Middle East peace George Mitchell has put off plans to visit the region this week, the State Department said on Tuesday. State Department spokesman P.J. Crowley said Mitchell will meet Israeli and Palestinian officials "as soon as possible," but not before a gathering of the quartet of Middle East peace mediators in Moscow on Thursday and Friday as he had planned. Israel's announcement of plans to build 1,600 housing units in East Jerusalem has strained ties with the United States, which has said it regarded last week's decision -- made public while Vice President Joe Biden was in Israel -- as an insult. The announcement has called into question U.S. efforts to launch indirect peace talks between the two sides after a 15-month hiatus in direct negotiations. Secretary of State Hillary Clinton last week made specific demands of Israeli Prime Minister Benjamin Netanyahu about the housing project and about showing commitment to U.S. mediated indirect peace talks, the State Department has said. "We do expect to have the Israeli response shortly," Crowley told reporters. "I would anticipate that, you know, very soon there is likely going to be a conversation between the secretary and Prime Minister Netanyahu. I am not forecasting that'll happen today."