The top U.S. military officer has arrived in Israel ahead of talks with Prime Minister Benjamin Netanyahu, President Shimon Peres and other high-level officials expected to focus on Iran's nuclear program and related security issues.

Israeli sources preparing for Friday's meetings say they expect U.S. Joint Chiefs of Staff Chairman Martin Dempsey to urge restraint amid fears the Jewish state is nearing a decision to attack Iran's controversial nuclear program.

The Israeli government says a nuclear armed Iran would be a threat to Israel's existence. Israel and the United States refuse to rule out military force to prevent such an outcome.

But U.S. officials publicly have urged Israel to avoid unilateral action and give more time for diplomatic pressure and sanctions on Iran to work. Israeli leaders recently have expressed concern that international sanctions have not curbed Iran's sensitive nuclear activities.

This week, the Israelis announced that a major joint military exercise with American troops planned for April has been postponed to the second half of the year, apparently to reduce regional tensions.

On Thursday, Turkey called for the resumption of talks between Iran and six major world powers over Tehran's nuclear program. Ankara says this could help defuse regional tensions that have intensified this month.

The talks with Iran – which involve the five permanent U.N. Security Council members and Germany – have been stalled for a year.

Turkish Foreign Minister Ahmet Davutoglu said all sides have expressed a willingness to resume discussions. Speaking at a joint news conference with his visiting Iranian counterpart, Davutoglu said Turkey is ready to host the negotiations.

Iranian Foreign Minister Ali Akbar Salehi called on the six countries to renew the talks without “excuses.”

Tensions between Iran and the West have risen in recent weeks as Washington and its EU allies have moved to strengthen sanctions on Tehran to pressure it to stop nuclear activities they suspect are aimed at developing weapons. Iran says its nuclear program is peaceful.

Tehran has responded to the tightening of Western sanctions by threatening to close the Strait of Hormuz, a vital passageway for global oil supplies. Washington has said such a move would not be tolerated.

The assassination of an Iranian nuclear scientist in Tehran earlier this month also prompted Iran to blame the attack on the United States and its ally Israel. Washington has denied involvement while Israel has not commented officially on the incident.

Iran's U.N. envoy said on U.S. television Thursday that Tehran would not attempt to block the Strait unless a foreign power seeks to “tighten the noose” in the growing showdown with the West.