An arms embargo and sanctions against 13 Syrian officials deemed responsible for the regime's savage crackdown on protesters has been officially adopted and will come into force Tuesday, an EU statement said.

"The (EU) Council has adopted a regulation and a decision providing for an embargo on exports to Syria of arms and equipment that could be used for internal repression, as well as a visa ban and an assets freeze," the statement said Monday.

Dozens of armored vehicles, including tanks and troops reinforcements, were deployed Thursday near the Syrian coastal town of Banias, an activist told Agence France Presse, contacted by telephone.

"It looks like they are preparing to attack the town, like they did in Daraa," the flashpoint town where the protest movement was born, he said.

The "brutality" of Syrian President Bashar al-Assad's response to anti-government protesters will lead to the downfall of his regime, according to Israel's Defense Minister Ehud Barak.

"I think that Assad is approaching the point where he will lose his internal legitimacy," Barak told Israel's Channel 10 television on Monday night.

Anti-regime protesters called for permanent sit-ins across Syria from Tuesday as the authorities were reported to have arrested more than 1,000 people in their latest crackdown on demonstrations.

"We call on Syrians in all regions to gather from Tuesday evening in all public places to organize sit-ins which will continue day and night," said a Facebook post by the opposition Syrian Revolution 2011 website.

Syrian forces arrested more dissidents Sunday in the flashpoint southern town of Daraa and in a Damascus suburb under siege for a week, after two days of fresh bloodshed, activists said.

Anti-regime protesters appealed for new protests to launch a "week of breaking the siege" imposed on Daraa and the Douma suburb, and other towns facing deadly crackdowns.

Turkey is against foreign intervention in Syria and believes the unrest-hit country should solve its own problems, Anatolia news agency quoted Foreign Minister Ahmet Davutoglu as saying on Sunday.

"We should work to prevent the possibility (of a military intervention in Syria). Foreign intervention in a country like Syria with a heterogeneous social structure might cause unwanted consequences," Davutoglu said.

More than 50 Syrians were killed as tens of thousands of protesters rallied for a "day of rage" after Friday prayers, defying warnings of a harsh crackdown, rights activists and officials said.

Protests against President Bashar al-Assad's regime were held in most major towns, witnesses said, in pro-democracy demonstrations after the Muslim weekly prayers as on past Fridays.

U.S. President Barack Obama must declare that his Syrian counterpart, Bashar al-Assad, has squandered his legitimacy and must step down, three key senators urged Thursday.

"We urge President Obama to state unequivocally -- as he did in the case of (Libyan leader Moammar) Gadhafi and (Egyptian President Hosni) Mubarak -- that it is time for Assad to go," Republican Senators John McCain and Lindsey Graham and independent Senator Joe Lieberman said in a joint statement.

Syria defiantly vowed to restore "security and stability" across the country despite growing international censure for its violent crushing of dissent, as activists called for more protests on Friday.

Growing anger at the regime's brutal crackdown on pro-democracy protesters, meanwhile, saw Britain on Thursday withdraw the Syrian ambassador's invitation to the wedding of Prince William and Kate Middleton.

The 15-nation U.N. Security Council failed on Wednesday to agree a statement to condemn the killing of Syrian protesters, diplomats said.

After talks ended in deadlock, western nations called for an immediate open meeting of the Security Council so that international anger over the crackdown by the Syrian government could be highlighted.