Some 4,000 Syrians have sought refuge in Turkey this week, fleeing fresh clashes pitting Kurdish fighters against the Islamic State (IS) group, a Turkish official said Friday.

The refugees are from Raqa province, an IS stronghold on Syria's border with Turkey. They left their war-torn country via the Akcakle frontier crossing in the southwest.

Two people were killed Friday when successive explosions hit a rally of the pro-Kurdish People's Democratic Party (HDP) in southeastern Turkey, two days ahead of legislative elections, a senior minister said.

Over 100 people were also wounded in the blasts in the city of Diyarbakir, said Agriculture Minister Mehdi Eker, who frequently represents the government on issues in the region, quoted by the Anatolia news agency.

A Turkish daily on Friday published images it said showed the Turkish spy agency helping to smuggle jihadists into Syria, the latest allegations by the newspaper accusing the authorities of aiding extremist groups across the border. 

The government had last week lambasted the Cumhuriyet daily for publishing video footage the paper said showed the National Intelligence Organization (MIT) helping send weapons to Syria early last year. 

Turkish authorities have detained a female Russian student as she attempted to cross into war-torn Syria, Russian authorities said Friday.

Moscow State University student Varvara Karaulova, 19, was found in the Turkish border town of Kilis after she vanished from the Russian capital, the interior ministry said in a statement. 

Turkish police on Thursday fired tear gas and water cannon to disperse hundreds of people protesting against an election rally by the pro-Kurdish People's Democratic Party (HDP) in eastern Turkey, days before parliamentary polls, reports said.

The clashes are the latest in a string of incidents in the run-up to Sunday's vote, where the HDP is trying to clear the 10 percent threshold for entering parliament as a party under proportional representation.

Turkish police detained a young French woman who crossed back into Turkey after joining Islamic State (IS) jihadists in neighboring Syria, a security official said on Thursday.

During a three-month stay in Syria, the woman married and then split up from a jihadist and was put in a jail operated by the IS group before being released, the official said.

Gunmen opened fire on a pro-Kurdish People's Democratic Party (HDP) campaign bus in southeastern Turkey on Wednesday, killing one person just days before parliamentary elections.

The victim, identified as the driver of the bus, was found dead with gunshot wounds to the head near the vehicle in the Karliova district of Kurdish-majority Bingol province, news agency Dogan reported. 

President Recep Tayyip Erdogan has launched aggressive attacks on media foes ahead of Turkey's most tightly-contested elections in over a decade, prompting fears of a clampdown on freedom of expression but also defiant vows not to stay silent.

Erdogan personally filed a criminal complaint against the editor-in-chief of the secular Cumhuriyet newspaper Can Dundar over a front page story it said proved Turkey had sent arms to rebels in Syria, warning he would "pay a heavy price".

Al-Qaida-linked al-Nusra Front denied on Wednesday that there was progress in the negotiations to release Lebanese hostages in a prisoner swap, saying the talks have been suspended.

The jihadists addressed the relatives of the hostages on their twitter account, saying: “Reports that the negotiations between us and General Security chief Maj. Gen. Abbas Ibrahim have been (successfully) completed are not true.”

Turkish President Recep Tayyip Erdogan on Tuesday filed a criminal complaint against a top daily newspaper and its editor for publishing images allegedly showing trucks belonging to the state intelligence service helping send weapons to rebels in Syria. 

Erdogan has accused the opposition daily Cumhuriyet and its editor-in-chief Can Dundar of "publishing images and information contrary to the truth" and "obtaining and disseminating secret information," the official Anatolia news agency reported.