Israeli Prime Minister Benjamin Netanyahu has told relatives of victims of last year's attack on Israeli tourists in Bulgaria that those responsible for the killings "will pay the price."

Netanyahu's office said Wednesday in a statement that the head of Israel's counterterrorism bureau told the victims' families in his name that "Israel will do everything so that those responsible for the crime will pay the price."

Iran's installation of new equipment at its Natanz nuclear plant will speed up enrichment efforts and complicate plans to prevent Tehran from building a weapons capability, Israel said on Sunday.

Speaking just before the formal start of talks to build Israel's new ruling coalition, Prime Minister Benjamin Netanyahu said the most important mission which will face the new government was preventing a nuclear Iran.

Israeli President Shimon Peres tasked Prime Minister Benjamin Netanyahu on Saturday with forming a new government after two days of intense talks with the parties recently elected to the new parliament.

"I have decided to charge Benjamin Netanyahu with forming the government," Peres said at a press conference at his official residence in Jerusalem, after 82 of the 120 members of the Knesset had declared in favor of the premier.

Israeli media on Friday warned that an alleged air strike on a convoy carrying arms from Syria to Hizbullah could set off a chain reaction, and reported troops on high alert in the country's north.

There was still no official Israeli comment on Syrian claims that Israeli warplanes bombed a military site near Damascus on Wednesday or on separate reports that its aircraft struck a weapons convoy along the Syria-Lebanon border.

Israel was on Thursday tightlipped over Syrian claims it had bombed a military site near Damascus, while stressing that any transfer of advanced weaponry to Hizbullah would cross a red line.

Israeli officials and the military refused to confirm or deny any involvement in the alleged attack and had no comment on separate reports from security sources that its warplanes had struck a weapons convoy along the Syria-Lebanon border.

Israel's premier Benjamin Netanyahu believes an Israeli strike on Iran's nuclear facilities could cause "significant damage" but only a U.S. attack could halt their operations, a newspaper said on Wednesday.

According to the Maariv daily, Netanyahu told a visiting delegation from the American Jewish Committee that only U.S. military action could completely halt Iran's nuclear program, which Israel and much of the world believes is a guise for building a weapons capability.

Israel said on Wednesday it had released $100 million of the tariffs and tax monies it collects on behalf of the Palestinian Authority, which were frozen last year as punishment for the U.N. bid.

But an Israeli official said it was a one-off measure to ease the financial crisis faced by the Palestinians and was not a sign that the transfers would be renewed.

U.S. President Barack Obama spoke to Israeli Prime Minister Benjamin Netanyahu on Monday to congratulate him on his Likud Party's showing in last week's general election.

"President Obama spoke today by telephone with Prime Minister Netanyahu to congratulate him on his party's success in winning a plurality of Knesset seats in Israel's recent election," a White House statement said.

Israel is increasingly worried that Syrian chemical weapons could fall into the hands of Hizbullah or Islamist militants and is taking military and diplomatic steps to prevent it, local media and a security source said Monday.

The Maariv daily said that Prime Minister Benjamin Netanyahu had "urgently dispatched" his national security advisor to Moscow, where he will meet Russian Foreign Minister Sergei Lavrov.

Israeli Prime Minister Benjamin Netanyahu on Sunday said he would seek a broad and stable coalition to deal with Iran's nuclear ambitions and the possible transfer of Syrian weapons.

"The entire region is raging and we must be prepared, strong, and determined in the face of any possible development," he told his cabinet ahead of its weekly meeting.