New sanctions against Syria have come into effect as Turkey says it has intercepted an arms shipment at sea.
The weapons were destined for the protest-wracked country during a weekend of deadly demonstrations in which at least 15 people were killed.
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.
Earlier this month, the EU adopted a ban on Syrian crude oil imports. That is expected to hit hard, as the EU buys 95 per cent 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, 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".
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.
At least 15 people were killed Saturday in the central Syrian province of Homs, in the latest government crackdown on pro-democracy protesters, according to Beirut-based activists.
Syrian security forces left several more dead and 30 injured near the Orontes River in the province, activists said.
Gunfire and blasts were also heard in the Qusayr area, south-east of Homs, a group of online activists reported.
Overnight protests were held in several parts of the central province. Videos posted online showed a group of protesters chanting "Praise the army defectors."
At least nine civilians were killed Friday in a government crackdown, as the European Union imposed a fresh round of sanctions on the regime of President Bashar al-Assad.
Meanwhile, the Syrian army's deputy chief of staff, Bassam Najm Eddin, died of a heart attack on Friday.
The official SANA news agency said on Saturday that his burial will take place in the martyrs' cemetery in Damascus.
Pelted with eggs
Also on Saturday, France's ambassador, 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.
Eric Chevallier had met with Ignace in the Christian quarter of Damascus's old city when young people and women began chanting slogans in support of Syrian President Bashar al-Assad, and threw eggs and stones at the French delegation when the ambassador was going to his car.
"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," Chevallier told AFP.
In-depth coverage of escalating violence across Syria
On Thursday, the French envoy visited four schools in Damascus and its surrounding suburbs to express his "deep concern" following reports that protests at those schools were repressed.
On Monday, French Foreign Minister Alain Juppe accused the Syrian regime of "crimes against humanity" and criticised the UN Security Council for failing to take a strong stand on the unrest.
On September 13, Chevallier and his US counterpart, Robert Ford, travelled to the Damascus district of Daraya to attend a condolence ceremony for slain Syrian activist Ghiyath Matar, who reportedly died under torture.
The office of the UN High Commissioner for Human Rights in Geneva has said the death toll from the crackdown on dissent in Syria 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.