Turkish authorities on Thursday launched dawn raids in Istanbul and the southern city of Mersin to arrest suspected members of an ultra-left group, a day after two of its militants attacked the Dolmabahce Palace in Istanbul, state media said.

Police detained over 40 suspected militants from the Marxist Revolutionary People's Liberation Party Front (DHKP-C) in Istanbul's Sariyer district on the shores of Bosphorus and several districts of Mersin, Anatolia news agency reported.

Turkey's election authority proposed November 1 as a possible date for early elections after the failure of attempts to form a coalition government following June 7 polls, the state-run Anatolia news agency reported Thursday. 

The proposal, presented to political parties before a final decision is made, comes three days ahead of an August 23 deadline for forming a new government.

Eight Turkish soldiers were killed on Wednesday in the deadliest attack by Kurdish militants since the government began an anti-terror offensive last month, as the country battles its most serious security and political crises in years.

An honor guard on duty outside the fabled Dolmabahce Palace in Istanbul was also attacked by suspected Marxist militants, with the country on edge after a wave of attacks in the last month.

Two militants on Wednesday launched an attack with guns and explosives on the Dolmabahce Palace in Istanbul, one of Turkey's main tourist attractions which also houses offices of the prime minister, the Istanbul authorities said in a statement.

Initial reports had said gunfire and an explosion was heard outside the palace, which was crowded with tourists at the height of the summer season.

President Recep Tayyip Erdogan on Wednesday said Turkey was heading rapidly towards snap polls after efforts to form a coalition government failed, creating an unprecedented situation in the country's modern history.

Erdogan spoke a day after Prime Minister Ahmet Davutoglu informed the president he had failed to form a coalition government following talks with the opposition.

A Turkish 17-year-old has been killed in clashes in Istanbul between police and a group allied to the outlawed Kurdistan Workers Party (PKK), the official Anatolia news agency reported Wednesday.

The clashes erupted late Tuesday when a group of around 20 people sought to hold what was described as an unauthorized demonstration in the Esenler district of Istanbul and opened fire on the police, the report said.

When Wael and his relatives from Syria climbed into an inflatable boat in the dead of night to cross the sea from Turkey to Greece, they abandoned all their belongings -- except their smartphones.

"Our phones and power banks are more important for our journey than anything, even more important than food," said Wael, a 32-year-old from the devastated Syrian city Homs who reached the Greek resort island of Kos on Thursday morning.

Nine people, including women and children, were killed when a boat smuggling Palestinians from Lebanon's northern port of Tripoli sank in Turkey's territorial waters, one of the survivors said on Wednesday.

The state-run National News Agency said the survivor told his relatives that the boat was carrying 40 Palestinians from Syrian camps, mainly Yarmuk in Damascus, who had taken refuge in Palestinian shantytowns in northern Lebanon.

U.N. humanitarian chief Stephen O'Brien has dampened expectations by Lebanese officials to allow a large number of Syrian refugees to return home and settle in safe zones.

“It is useless to discuss about safe zones in Syria unless there is a clear intention to guarantee the security of those willing to return to these areas,” O'Brien told An Nahar daily in an interview published on Wednesday.

Turkey's Prime Minister Ahmet Davutoglu on Tuesday met President Recep Tayyip Erdogan to formally acknowledge he cannot form a coalition government, paving the way for new elections just months after June polls.

In line with procedure, Davutoglu was to return to Erdogan the mandate he received from the president on July 9 to begin coalition talks with opposition parties, the official Anatolia news agency said.