New sanctions against Syria come into effect on Saturday as Turkey said it had intercepted an arms shipment at sea destined for the protest-wracked country after another day of deadly demonstrations.
The sanctions came as 13 civilians were killed by security forces, nearly all in the central Homs region, a rights group said.
Both the European Union and Switzerland have targeted Syria's oil sector in new sanctions that bite from Saturday, with the EU banning new investments there and also prohibiting the delivery of bank notes to Syria's central bank.
The EU has also added two individuals and six companies to a list of people and entities facing an assets freeze and travel ban.
The new measures are the seventh set of EU sanctions imposed to punish the regime of President Bashar al-Assad for its relentless crackdown on dissent that erupted in mid March.
Meanwhile, France's ambassador said he was attacked on Saturday by a crowd throwing stones and eggs at him after he met with Greek Orthodox Patriarch Ignace IV in the Syrian capital.
"The Shabiha (a pro-regime militia), some of whom had metal bars in their hands, and women threw eggs and stones in my direction and in the direction of my team, and looked threateningly at us while we were returning to our two cars," Eric Chevallier told AFP.
Earlier this month, the EU adopted a ban on Syrian crude oil imports. That is expected to hit hard, as the EU buys 95 percent of Syrian oil exports, providing a third of the regime's hard currency earnings.
The Swiss sanctions put an embargo on the import, sale and transport of Syrian oil and oil products.
Turkey, formerly a key regional friend of Syria, has intercepted a shipload of weapons bound for Syria, the Anatolia news agency reported.
"Turkey has arrested a ship flying the Syrian flag and carrying weapons," it quoted Prime Minister Recep Tayyip Erdogan as telling reporters in New York, where he attended the UN General Assembly.
Erdogan did not say when and where the ship was stopped.
The Turkish leader lashed out at Assad last week, telling him the era of oppressive dictators was past.
Erdogan said he had told Damascus arms shipments would be stopped, adding: "If in the future arms shipments are made by air or land, we will stop and seize them as we have done."
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On Tuesday, Erdogan said he had broken off dialogue with Damascus and warned of sanctions, after talks with US President Barack Obama in which the two discussed the need to "increase pressure" on Assad's regime.
In the latest cracdown, 12 people were killed in the central Homs region and one in Hama, the Syrian Observatory for Human Rights said.
"Twelve civilians were killed in Qusseir during search operations for people wanted by the army and security forces in this locality," the Observatory told AFP in Nicosia.
Security forces shot and killed another person in the nearby city of Hama, it added.
Syrian troops reinforced their numbers on the border with Lebanon, particularly outside Qusseir and the crossing at the Lebanese town of Qaa, to close off an escape route used by refugees trying to escape the violence, witnesses said.
Two wounded were evacuated across the border on Saturday they said, adding that the flow of refugees had nearly stopped after the added military presence.
In addition, the bodies of two people who had gone missing in recent days were handed over to their families by the Syrian authorities, while another died of wounds suffered on Friday.
Nine people were killed by security forces during anti-regime protests in the Homs area on Friday, the Britain-based Observatory reported.
The office of the UN High Commissioner for Human Rights in Geneva has said the death toll from the crackdown on dissent since March 15 has risen to more than 2,700.
Damascus does not accept that popular opposition to the authorities exists, instead blaming "armed gangs" and "terrorists" for trying to sow chaos.
Amnesty International said on Friday it had uncovered evidence of the gruesome death of an 18-year-old girl in custody in Syria, and said it had compiled the names of more than 2,200 people reported killed during the unrest.
The London-based rights watchdog said the girl's mutilated body was discovered in a Homs mortuary last week, two months after her arrest.
The family of Zainab al-Hosni discovered her body "by chance" and "in horrific circumstances," while collecting the corpse of her activist elder brother Mohammad Deeb, it said in a statement.
He too had apparently been tortured and killed in detention. But his sister's body had been decapitated and her arms and skin removed, the rights group said.
The Syrian high command, meanwhile, reported the death on Friday from a heart attack of the army's deputy chief of staff, General Bassam Najm Eddin Antakiali, the official SANA news agency reported.