Serbia accused Recep Tayyip Erdogan on Friday of meddling in the country's affairs after the Turkish Prime Minister said that "Kosovo is Turkey" during a recent visit to the former Serbian province.

Kosovo broke away from Serbia in 2008 but Belgrade still refuses to recognize its independence.

Turkish police fired tear gas canisters on students gathered to protest the beginning of controversial works on a road through their university campus in Ankara, an AFP photographer reported.

Security forces shielded workers and diggers as they began uprooting trees in a park on the site of Middle East Technical University (METU) in the Turkish capital on Friday night.

Turkey's appeals court Wednesday upheld the convictions of scores of top retired military officers over a 2003 coup plot but overturned jail sentences handed to dozens of lower-ranking defendants.

The court in Ankara confirmed an earlier ruling that found the former commanders of the army, navy and air force guilty of plotting to oust Prime Minister Recep Tayyip Erdogan's Islamic-rooted government and sentenced them to 20 years behind bars.

Turkish Prime Minister Recep Tayyip Erdogan has hinted he would be willing to run for president in next year's elections, a move analysts have been expecting of the conservative premier who is approaching his term limit.

"For the moment, nothing is certain," Erdogan said in a television interview late on Thursday, when asked whether he would run in the August 2014 poll, the first in which the head of state will be elected by voters instead of parliament.

Syrian President Bashar Assad warned Turkey it will "pay dearly" for supporting rebels fighting to overthrow his regime, in an interview broadcast Friday on Turkish television.

"In the near future these terrorists will have an impact on Turkey. And Turkey will pay very dearly for its contribution," Assad told the opposition station Halk TV.

Turkey on Monday announced it would lift a ban on women wearing headscarves in most public offices, following other measures critics say are aimed at Islamizing the staunchly secular country.

In a major speech to introduce political reforms, Prime Minister Recep Tayyip Erdogan said that, with a few exceptions, civil servants would be allowed to wear headscarves after a long-standing ban is overturned.

Turkey on Monday moved to scrap restrictions on the use of the minority Kurdish language among democratic reforms designed to revive the stalled peace process with the banned Kurdistan Workers' Party (PKK).

But the proposed reforms fell short of satisfying a key Kurdish politician.

Turkish security forces have recaptured all but one of 18 escaped prisoners detained for suspected links with the outlawed Kurdistan Workers' Party (PKK), the interior minister said Thursday.

"Seventeen of the escapees have been apprehended. Security forces are looking for the last one," Muammar Guler said on his official Twitter account.

Turkish Prime Minister Recep Tayyip Erdogan on Tuesday defended the military's downing of a Syrian helicopter which he said violated its airspace.

"The Turkish Armed Forces did what's necessary," Erdogan told a press conference, a day after its warplanes shot down the military helicopter which was detected two kilometers (1.2 miles) inside Turkish airspace.

Riot police used tear gas and water cannon to disperse anti-government protesters in several Turkish cities overnight Monday, as demonstrations against the Islamic-rooted cabinet simmered across the country, media reported.

In Istanbul's Kadikoy district, which has become the focal point of the demonstrations, hundreds of protesters set up barricades, which they then set on fire, according to NTV television.