Israel's President Shimon Peres is to travel to Washington late on Monday for his last foreign visit before leaving office next month, his office said.

"Peres will depart tonight on a diplomatic visit to the United States of America in what will be his final foreign trip" before stepping down in July at the end of his seven-year presidency, a statement said.

Syria urged the United Nations on Monday to condemn Israel's "flagrant violation" of its territory over air raids it said killed four of its soldiers in the Israeli-held Golan Heights.

"The Israeli occupation forces on Sunday and Monday carried out a new attack against positions inside Syrian territory, which constitutes a new, flagrant violation of the 1974 Separation of Forces Agreement, of the U.N. charter and international law," Syria's foreign ministry said in letters addressed to the U.N. secretary general and to the Security Council.

Israeli troops detained 37 Palestinians in the West Bank during the night as its arrest campaign entered its 11th day on Monday, with no sign of three teenagers thought kidnapped by Hamas.

Since the youths disappeared from a hitchhiking stop in the southern West Bank on June 12, Israel has been rounding up hundreds of Palestinians in a bid to find them, while also dealing a crushing blow to the Islamist movement's West Bank network.

At least 10 Syrian soldiers were killed in Israeli overnight air raids on positions near the Israeli-held Golan Heights, the Syrian Observatory for Human Rights monitoring group said on Monday.

"At least 10 Syrian soldiers were killed in Israeli raids against military positions next to the occupied part of the Golan. Nine missiles were fired by aircraft and at least two tanks and two artillery batteries were destroyed," the Observatory said.

Israeli troops detained 37 Palestinians in the West Bank overnight as its arrest campaign entered its 11th day on Monday, with no sign of three teenagers thought kidnapped by Hamas. 

Since the youths disappeared from a hitchhiking stop in the southern West Bank on June 12, Israel has been rounding up hundreds of Palestinians in a bid to find them, while also dealing a crushing blow to the Islamist movement's West Bank network. 

Israel carried out retaliatory air raids on Syrian army positions in the Golan Heights overnight after a teenager on the Israeli side was killed in an attack from Syria, the army said early Monday.

"The IDF (Israeli army) targeted nine Syrian army positions in response to the earlier attack that originated in Syria killing an Israeli teenager and injuring two other Israeli civilians," an army spokesman said.

The teenage son of an Israeli defense ministry contractor was killed on the Golan Sunday in the most serious incident on the plateau since the Syrian civil war erupted in 2011.

Israel's defense ministry and the army said the 15-year-old was killed when a blast hit the car he was traveling in with his father and another contractor, both of whom were wounded.

Israel's foreign minister said Sunday a final decision has yet to be made on his threat to expel the U.N.'s peace envoy for offering to help transfer Qatari funds to Gaza.

Avigdor Lieberman was reported to have said by Channel Two television that he wants to declare Robert Serry persona non grata and expel him from Israel over the alleged offer.

Israeli troops shot dead two Palestinians in the West Bank on Sunday in separate clashes that erupted as they made more arrests in the hunt for three missing teenagers.

Their deaths raised to four the number of Palestinians killed since the army began a massive search for the Israeli students who disappeared on June 12 while hitchhiking in the southern West Bank.

Israeli security forces have arrested 10 more Palestinians in the West Bank as they press their search for three teenagers believed to have been kidnapped, the army said on Saturday.

"Ten members of Hamas were arrested during the night, bringing the number of Palestinians arrested since the beginning of the operation to 340, 240 of whom are affiliated to Hamas," the army said in a statement.