Syrian President Bashar al-Assad threatens to "fan the flames" of sectarian conflict not only in Syria but in the wider region, U.S. Vice President Joe Biden said in talks with the Turkish president, a U.S. official said Saturday.

"Assad and his regime are the source of instability in Syria now and pose the greatest danger to fanning flames of sectarian conflict not only in Syria but beyond," Biden told Abdullah Gul when they met Friday, the senior official told reporters.

Turkish troops killed three Kurdish rebels in southeast Turkey overnight, local security sources said on Saturday.

The army launched an operation against militants of the Kurdistan Workers' Party (PKK) in a rural area near Lice on Friday night, they said.

U.S. Vice President Joe Biden urged Syria's Bashar Assad to quit, in a Turkish newspaper interview published Friday, adding to growing global pressure on the regime over its crackdown on dissidents.

"The United States' position on Syria is clear. The Syrian regime must end its brutality against its own people and President Assad must step down so a peaceful transition that respects the will of the people can take place," Biden told the Hurriyet daily.

Syria's civilian opposition and army rebels have agreed to coordinate their struggle against President Bashar Assad's regime, an official said Thursday.

The first meeting between the Syrian National Council and the Free Syrian Army earlier this week in Turkey appeared to mark a change of tack from the SNC's previous reluctance to back the armed struggle.

A Libyan gunman wounded two people Wednesday in one of Istanbul's top tourist attractions Wednesday before being killed by police after an hour-long shootout, authorities and local media said.

The man entered the Topkapi Palace on the banks of the Bosphorus Strait and began shooting in all directions with a pump action shotgun, NTV television quoted Istanbul police Chief Huseyin Capkin as saying.

Turkey on Wednesday slapped economic sanctions on the Syrian regime, freezing assets of Syrians involved in the government's crackdown on protesters, suspending ties with Syria's Central Bank and banning all military sales.

Foreign Minister Ahmet Davutoglu told a news conference that Syrian President Bashar Assad has wrongly ignored calls from the international community to stop its bloody crackdown on protesters.

A 5.0 magnitude tremor shook the eastern Turkish province of Van overnight without causing damage or casualties in an area already ravaged by two deadly earthquakes, media said on Tuesday.

The tremor at about 00:27 GMT panicked the region's residents, many of them still living in tent camps since an October 23 earthquake killed more than 600 people, the Anatolia news agency reported.

Turkey may consider setting up a buffer zone on its border in coordination with the international community in the event of a massive exodus of refugees from Syria, its foreign minister said on Tuesday.

"We are preparing for every scenario," Foreign Minister Ahmet Davutoglu told Kanal 24 television channel when asked whether Turkey was mulling the creation of a buffer zone.

Turkey plans to bypass Syria for regional trade if conditions in the neighboring country deteriorate, the country's transport minister said on Tuesday.

"If conditions aggravate in Syria, we are planning to shift (road) transport to Iraq by opening new gates," Transport Minister Binali Yildirim was quoted as saying by the Anatolia news agency.

French military forces are training armed Syrian rebels in Turkey and Lebanon to fight the government of Syrian President Bashar Assad, a Turkish newspaper has reported.

According to Milliyet, as cited by The Islamic Republic News Agency, IRNA, the French forces are training the so-called Free Syrian Army to wage war against Syria's military.