The head of the US military arrived in Israel on Sunday amid the largest-ever military exercise between the two countries.

Gen. Martin Dempsey, chairman of the US Joint Chiefs of Staff, met Sunday with Defense Minister Ehud Barak at the beginning of his visit, which also saw him observe the Austere Challenge 12 drill involving thousands of troops from Israel and the US.

Barak remarked after his meeting with Dempsey that “the security relationship between the US and Israel is deeper and stronger than it has been in recent years.”

Dempsey will also meet his Israeli counterpart, IDF Chief of Staff Lt. Gen. Benny Gantz, and President Shimon Peres.

Dempsey’s visit to Israel was his second in 2012, having made the trip in January to meet with IDF brass. Chief among subjects discussed by Dempsey is likely Israeli and American security cooperation vis-à-vis Iran’s nuclear program.

Dempsey has been outspoken against Israel carrying out a unilateral strike on Iran, being quoted by The Guardian in August saying an Israeli strike would not be able to stop Tehran’s drive toward nuclear capability and declaring that he would not wish to be “complicit” in an Israeli strike.

Dempsey is scheduled to oversee elements of Austere Challenge 12, an air-defense drill that includes more than 3,500 Americans and 1,000 Israeli troops. The forces are training their ability to work together against a range of threats facing Israel.

Among other things, the joint exercise is testing multiple Israeli and American air-defense systems against incoming missiles and rockets from as far away as Iran.