Israel is gearing up for a deterioration in the regional situation, with a growing number of new threats facing the Jewish state, Prime Minister Benjamin Netanyahu said on Wednesday.

Netanyahu made the comments as he watched an exercise simulating the response to a chemical attack on a residential neighborhood in Jerusalem as part of an annual civil defense drill.

Israel's Prime Minister Benjamin Netanyahu has ordered his cabinet to stay silent on the issue of Russian missile deliveries to Syria, public radio said on Wednesday.

His remarks came after several ministers criticized Moscow's arms deals with Damascus and raised the possibility of an Israeli response should the Jewish state feel under threat.

Israel launched on Sunday a national civil defense drill, which the army said will this year focus on the threat of unconventional weapons at a time of growing regional tensions.

"The threats against the Israeli home front have significantly increased in recent years," Prime Minister Benjamin Netanyahu said at the beginning of the weekly cabinet meeting in remarks relayed by his office.

U.S. Secretary of State John Kerry on Thursday admitted there was skepticism and cynicism about his efforts to broker new talks between Israelis and Palestinians, as he made his fourth visit to Israel.

Flying in from a night of diplomacy in Amman over the war in Syria, Kerry went straight into talks with Prime Minister Benjamin Netanyahu as he pursued his bid to kick-start negotiations frozen since late 2010.

Israel is "acting" to prevent Syrian weapons reaching Hizbullah and will continue to do so, Prime Minister Benjamin Netanyahu said on Sunday.

His remarks came two weeks after Israel carried out air strikes near Damascus, which a senior Israeli source said were aimed at preventing the transfer of sophisticated Iranian arms to Hizbullah.

Visiting German Foreign Minister Guido Westerwelle on Friday reaffirmed his country's friendship for Israel in "challenging times" for the region, as tensions mount over the Syrian conflict.

"I want to underline that in these challenging times Germany stands alongside its Israeli partners," Westerwelle said at the start of talks in Jerusalem with Prime Minister Benjamin Netanyahu, calling his host a "dear friend."

Israeli Prime Minister Benjamin Netanyahu is to hold talks on Tuesday with Russian President Vladimir Putin on the conflict in Syria, the Kremlin said, amid concerns Moscow plans to deliver advanced missiles to the Damascus regime.

"During the meeting an exchange of opinion is planned on key aspects of bilateral ties," the Kremlin said in a statement.

Israeli Premier Benjamin Netanyahu is "fully determined" to try to halt sales by Russia of advanced missiles to Syria when he visits Moscow for talks with President Vladimir Putin, a minister said Sunday.

A reported Russian plan to sell Damascus S-300 missile batteries "worries us at the highest level and the prime minister is fully determined that this contract should not be fulfilled," Energy and Water Minister Silvan Shalom, a member of the security cabinet, told public radio.

Israeli Prime Minister Benjamin Netanyahu will visit Russia for talks with President Vladimir Putin, officials said Saturday, amid concerns Moscow may be about to deliver advanced missiles to Syria.

Putin's spokesman Dmitry Peskov confirmed the visit to Agence France Presse, but declined to give details, although he told the Interfax news agency it was being planned for next week.

Israel's Prime Minister Benjamin Netanyahu met President Xi Jinping in Beijing on Thursday, during a five day visit that the newly installed Chinese leader said had already "yielded rich fruits".

Netanyahu met Xi after the Israeli leader witnessed with China's Premier Li Keqiang the signing of a series of trade and cultural deals the previous day.