Turkey and Syria have begun their first-ever joint land forces exercise as part of a three-day drill that Ankara said will “boost friendship, cooperation and confidence” between the two countries. Turkey has showed signs in the past year that it has begun to distance itself from Israel.

Defense Minister Ehud Barak said on Tuesday that the joint exercise is “a worrisome development” but that he “believes strategic relations between Israel and Turkey will overcome the need for Syria to participate in this exercise.”

Syria and Turkey plan to sign a letter of intent to promote cooperation in the defense industry, and Syria is attending an international defense industry exhibition in Istanbul this week. However, sources told Turkey’s Today's Zaman news website that the letter of intent involves political relations and “does not mean that the two countries will immediately enter into cooperation in arms production."

Turkey has tried to become a leader in Middle East negotiations and last year mediated indirect talks between the former Olmert administration and Syria. It has also been one of the forces behind efforts to forge unity between the Hamas and Fatah factions in the Palestinian Authority.

In addition, Ankara has announced it is proceeding with a massive weapons sale to Lebanon despite Israeli objections due to the growing dominance of the Hizbullah terrorist organization in Lebanese politics. Hizbullah may win a plurality in the June election.

Relations with Israel soured earlier this year during the Operation Cast Lead counterterrorist campaign, when Turkish Prime Minister Recep Tayyip Erdogan walked out of a panel discussion in the presence of President Shimon Peres. Erdogan was wildly cheered when he returned home.

Turkey, a popular vacation destination for Israeli tourists until the Erdogan incident, has been Israel’s closest Muslim ally. Trade between the two countries grew by 23 percent last year, and both countries have staged joint naval exercises. However, Alon Liel, Israel's former foreign ministry official in Turkey, has stated that relations between Turkey and Israel have been harmed.

Turkey also is a member of the North Atlantic Treaty Organization (NATO). Its border with Syria is along the Kurdish area that has been involved a long conflict with the Turkish government.