Europe will strengthen sanctions imposed on Damascus in a bid to boost pressure on the regime after China and Russia vetoed a U.N. resolution on the Syrian crisis, France said on Sunday.

"Europe will again harden sanctions imposed on the Syrian regime. We will try to increase this international pressure and there will come a time when the regime will have to realize that it is completely isolated and cannot continue," French Foreign Minister Alain Juppe said on BFMTV television.

Rival Palestinian factions Hamas and Fatah agreed at a meeting in the Qatari capital on Sunday that presidential and legislative elections must be held "quickly," a top official told Agence France Presse.

Palestinian President Mahmoud Abbas and Hamas chief Khaled Meshaal met to explore the formation of an interim Palestinian government to oversee the preparations for the polls and discuss the implementation of a reconciliation deal.

U.S. Secretary of State Hillary Clinton vowed Sunday to bolster existing sanctions against the Syrian regime and seek further ones to block funding and arms shipments to Damascus.

Seeking other ways to turn the screws on Assad a day after Russia and China vetoed a resolution on Syria, Clinton said Washington will also work with Syria's friends worldwide to support the peaceful aims of the opposition.

The Arab League will continue working to end political violence in Syria to stave off foreign military intervention after Russia and China blocked a U.N. resolution condemning Damascus, league chief Nabil al-Arabi said on Sunday.

Arabi said the 22-member organization would continue working with the Syrian regime and opposition for a "political solution" to Damascus' deadly crackdown on pro-democracy protests.

Egypt is to try 44 people, including Americans, over the funding of non-governmental organizations, a day after the United States said aid to Cairo will be reviewed over the crackdown.

"Forty-four people, including Egyptians, 19 Americans and other nationalities, have been referred to the Cairo criminal court in the NGO funding case," the source told Agence France Presse, adding that a travel ban on all remained in place.

Crowds of Syrians chanting anti-Russian slogans entered Moscow's embassy in Tripoli on Sunday and hoisted the new Syrian flag on the building, an Agence France Presse journalist and a Syrian activist said.

The journalist said about 200 Syrians entered the embassy and first removed the Russian flag.

Jordanian Islamists on Sunday called on Muslims and Arabs to boycott Russian and Chinese products after the two countries vetoed a U.N. Security Council resolution condemning Syria's regime over bloodshed.

"By vetoing the resolution, Russia and China have shown that they are taking part in the killing of Syrian people," Hammam Saeed, the leader of the powerful Muslim Brotherhood, said on the group's website.

Syrian security forces killed 36 people across the country on Sunday, most of them in the central protest hub of Homs, activists said, after nine regime troops were killed overnight at the hands of rebels according to a rights group.

The Local Coordination Committees, the main activist group spurring protests on the ground, said security forces killed 22 people in Homs, six in the flashpoint northwestern province of Idlib, five in the restive countryside around Damascus, two in the southern province of Daraa and one in the northern province of Aleppo.

Russian Foreign Minister Sergei Lavrov will ask President Bashar Assad for rapid reforms on a visit to Syria this week, his ministry said Sunday, as Moscow hit back at Western outrage over its U.N. veto.

Lavrov's visit to Damascus on Tuesday alongside the head of Russia's Foreign Intelligence Service (SVR) will aim to stabilize the situation in Syria by winning the implementation of "rapid" reforms, the foreign ministry said.

Prime Minister Benjamin Netanyahu said on Sunday that economic and military might are Israel's only guarantee for peace and security following the latest developments in Iran and Syria.

"In the past few days we received a reminder of what kind of neighborhood we live in," Netanyahu said at the start of the weekly cabinet meeting.