Germany said Monday it was "deeply concerned" about Israeli plans for new settlements but would not "for the moment" summon its ambassador to Berlin.

Ahead of talks this week between Chancellor Angela Merkel and Israeli Prime Minister Benjamin Netanyahu, German government spokesman Steffen Seibert called on Israel to withdraw its plan to build new Jewish settler homes.

Three Israeli settlers were arrested on Monday on suspicion of having carried out a string of "price-tag" attacks against Palestinian property, Israeli police said.

"The police arrested three suspects in their 20s after they were involved in criminal incidents with nationalistic motives," said police spokesman Micky Rosenfeld.

U.S. Secretary of State Hillary Clinton on Monday issued a "strong warning" to the regime of Bashar Assad over the potential use of chemical weapons against the Syrian people.

"This is a red line for the United States," Clinton said after meeting Czech Foreign Minister Karel Schwarzenberg in Prague.

Israeli forces from the Shin Bet internal security agency shot dead a Palestinian in the West Bank on Monday after he rammed their car and attacked them with an axe, the intelligence agency said.

In a statement, Shin Bet said a number of their agents were travelling in a military jeep in the West Bank when a Palestinian car slammed into them, flipping their vehicle.

A Saudi F-15 fighter with only the pilot on board crashed into Gulf waters while on a training mission in the kingdom's Eastern Province, the defense ministry announced on Monday.

The plane fell into "Saudi territorial waters and the search for the pilot is still ongoing," the ministry said, adding that an investigation has been launched into the cause of the crash.

The Syrian army bombarded southern districts of the capital and suburbs overnight as part of an assault aimed at driving rebels out of footholds around Damascus, a monitoring group said on Monday.

The Syrian Observatory for Human Rights said artillery gunners targeted the districts of Hajar al-Aswad and Tadamun as well as the Palestinian refugee camp of Yarmuk in southern Damascus.

Israel's ambassador to Britain was summoned to the Foreign Office on Monday to discuss plans for new settlements, officials said, warning of "strong reaction" to the proposals.

Foreign Office minister Alistair Burt called in Daniel Taub to warn that settlement building threatens the two state-solution and makes progress on peace talks with the Palestinians harder to achieve, the Foreign Office said.

Even if NATO foreign ministers approve Turkey's request to deploy Patriot missiles on the border with Syria as expected, it will still take some weeks to get them in place, a top U.S. official said Monday.

The United States was "hopeful that NATO will be in a position to respond positively and agree to help Turkey bolster its air defences," a senior State Department official said.

U.N. leader Ban Ki-moon warned Sunday that if Israeli implemented its latest plan for new settlements it would deal an "almost fatal blow" to any prospects for peace with the Palestinians.

Israel's announcement about the 3,000 Jewish settler homes, whose planned location was not revealed, came in the wake of a historic vote by the United Nations General Assembly to upgrade Palestine's diplomatic status.

Israel must provide an "immediate and detailed explanation" for its targeting of journalists and media buildings during last month's Gaza conflict, the Committee to Protect Journalists said on Sunday.

In a letter to Israeli Prime Minister Benjamin Netanyahu, the watchdog said it was "gravely concerned that Israeli airstrikes targeted individual journalists and media facilities in the Gaza Strip between November 18 and 20."