Israeli Prime Minister Benjamin Netanyahu said Tuesday that German-supplied submarines were "very important" for his country's defense, after a media report that Israel was fitting the vessels with nuclear warheads.

"Germany has underlined its commitment to Israel's security in particular with the sale of another submarine," Netanyahu told the daily Bild. "It is a very important addition to our national security."

When Sandra Tamari arrived at Israel's international airport, she received an unusual request: A security agent pushed a computer screen in front of her, connected to Gmail and told her to "log in."

The agent, suspecting Tamari was involved in pro-Palestinian activism, wanted to inspect her private email account for incriminating evidence. The 42-year-old American of Palestinian descent refused and was swiftly expelled from the country.

Regime forces went on the offensive against rebels on Tuesday, seizing a town in the central province of Hama, as at least seven people including an army colonel were killed in violence across Syria, monitors said.

After three days of bombardment, troops and pro-regime militiamen backed by tanks and armored cars entered Kfar Zita, the Syrian Observatory for Human Rights said, adding that rebel fighters had withdrawn.

Syrian government troops fought deadly battles with armed rebels on Monday as the European Union pushed for an end to a split with Russia over how to end the 15-month bloodshed.

In talks in Saint Petersburg with Russian President Vladimir Putin, EU President Herman Van Rompuy said the EU and Russia "might have some divergent assessments" of the situation in Syria.

The opposition Syrian National Council will meet at the weekend to replace Burhan Ghalioun who resigned as leader of the bloc late last month, SNC officials said on Monday.

The meeting will take place Saturday and Sunday in Istanbul, where a vote might be waived since there is a "consensus" candidate, the sources said on condition of anonymity.

Syrian President Bashar Assad was lying when he denied his regime had any involvement in the massacre of more than 100 civilians near the central town of Houla, the White House said Monday.

Asked if Assad lied at the weekend when he denied his forces fired on innocent civilians near Houla, President Barack Obama's spokesman, Jay Carney, said: "Yes.

Egyptian politicians, including three of the losing candidates in the first round of the presidential election, joined forces on Monday with youth groups demanding the suspension of a second-round runoff.

The joint call is aimed at putting pressure on election frontrunner Ahmed Shafiq, a former Hosni Mubarak premier, who is due to square off against Muslim Brotherhood candidate Mohammed Mursi on June 16-17.

A Syrian opposition group announced Monday that they are creating a new military structure consisting of 12,000 fighters to topple the regime of the Syrian President Bashar Assad.

"We announce today the unification of all fronts in a single center to bring about the collapse of the oppressing regime," Khaled al-Okla from the Syrian Revolutionaries Front (SRF) read from a statement at a press conference.

Slovakia said Monday it has summoned the Syrian ambassador over recent violence in Syria, particularly the Houla massacre, which claimed 108 lives including those of 49 children, according to UN figures.

"The ministry is deeply concerned about the continuous violation of human rights in Syria and calls for an early and full implementation of the peace plan of international envoy Kofi Annan," the Slovak foreign ministry said in a statement.

Syrian President Bashar Assad is determined to crush the rebellion against his regime, even at the cost of triggering a civil war in the country, bolstered by support from Moscow, analysts say.

"He has been ready to fight to the end right from the start and as long as he has Russia's support he believes he will win," Middle East expert Agnes Levallois told Agence France Presse.