Overwhelmed by an influx of mostly Syrian immigrants, Bulgaria has taken steps to secure its EU border -- including building a barbed-wire fence -- but now faces criticism from rights groups.

The 30-kilometer (19-mile) fence, standing three meters (10 feet) high and fortified with razor wire coils, was completed this week.

New U.N. peace envoy to Syria Staffan de Mistura will meet members of the Security Council on Friday as he sets out to revive efforts to end the devastating war.

Diplomatic sources said it will be a first opportunity to discuss the way forward with De Mistura, an Italian-Swedish diplomat with experience in Iraq and Afghanistan.

Four people were killed and another 22 wounded by rebel mortars fired into central Damascus Wednesday, just as President Bashar Assad was sworn in for a third term, state news agency SANA said.

The mortars came minutes after Assad's inauguration speech ended.

Syrian President Bashar Assad on Wednesday hailed Hizbullah's fighters who “stood side by side” with the Syrian army, thanking those who considered supporting Damascus equivalent to “defending south Lebanon.”

“I salute the loyal heroes of the Lebanese resistance, who stood side by side with the heroes of our army,” Assad said in a triumphant speech delivered after he took the oath of office for a new seven-year term.

Turkey is to take "drastic measures" to deal with the influx of tens of thousands of Syrian refugees into its biggest city Istanbul, including forcibly sending them to camps in the southeast, the city's top official said Wednesday.

Istanbul governor Huseyin Avni Mutlu said that there were now 67,000 Syrian refugees in the city and legislation would now be adopted that could see them effectively expelled from the city of 15 million to refugee camps closer to Syria.

President Bashar Assad was sworn in Wednesday for a new term, warning Western and Arab governments of the backfire they face for their support of the armed revolt in Syria.

In a triumphant speech before an invited audience after taking the oath of office at a red carpet ceremony in Damascus, Assad mocked the "fake spring" of the 2011 Arab uprisings.

United Nations Special Coordinator for Lebanon Derek Plumbly described on Wednesday the situation along the southern Lebanese border as “dangerous,” stressing that all sides must exercise self-restraint.

“The recent developments are a serious source of concern, especially after rockets (hit Israel) for four consecutive days,” Plumbly said in an interview with An Nahar newspaper.

Aid agencies said Tuesday they were ready to truck desperately-needed supplies to 2.9 million more Syrians after the U.N. Security Council finally passed a resolution backing cross-border convoys.

"U.N. agencies have supplies ready to go to all of those hard to reach areas. They had those in place for some time," Amanda Pitt, spokeswoman for the U.N.'s humanitarian aid coordination arm, told reporters.

The Change and Reform bloc led by MP Michel Aoun on Tuesday accused Progressive Socialist Party leader MP Walid Jumblat of approaching the issue of presidential elections according to “narrow calculations,” as it urged Lebanese authorities to communicate with Damascus over the “unbearable” refugee crisis.

“Public voting by people is the peak of democracy and there are mechanisms to implement our democracy in this regard,” former labor minister Salim Jreissati said after the bloc's weekly meeting, reciting a written statement.

New British Foreign Secretary Philip Hammond on Tuesday ruled out any possibility of working with Syrian leader Bashar Assad over the country's civil war.

Prime Minister David Cameron announced earlier Tuesday that Hammond was leaving his post as defense secretary and taking over from William Hague.