Turkey shuts border crossings as fighting worsens around Syria's Aleppo

ISTANBUL (Reuters) - Turkey has closed two border crossings with Syria as a security precaution as fighting around the northern Syrian city of Aleppo intensifies, Turkish customs and government officials said on Wednesday. The crossings at Oncupinar and Cilvegozu in Turkey's southern Hatay province have been shut to vehicles and individuals crossing from Syria since Monday, customs officials at both posts told Reuters. "Turkey has some security concerns and it is natural for measures to be taken based on the threat assessment conducted. This is what is also expected by Turkey by the international community," said an official at a government agency, who declined to be identified. He did not say when the crossing would be reopened. Humanitarian aid will not be affected, the government official said. Syrians with passports are still allowed to cross into Syria. Turkey has kept its borders open to refugees since the start of Syria's civil war four years ago, but it has come under criticism for doing too little to keep foreign fighters crossing and joining militant groups including Islamic State. Thousands of foreigners from more than 80 nations including Britain, China and the United States have joined the ranks of Islamic State and other Islamist groups in Syria and Iraq, many crossing through Turkey. On Wednesday, Ankara said it had detained 16 Indonesians from three families who were trying to cross into Syria. Aleppo, around 50 km (30 miles) south of the border, is divided between government forces and insurgent groups fighting to topple President Bashar al-Assad in a conflict estimated to have killed 200,000 people. Dozens of people were killed last Wednesday when insurgents attacked a Syrian government security building in the city, bombing it and then launching a ground assault. The closure of the Turkish border posts also comes after an air strike on Sunday in northwestern Syria, close to the border, hit a camp used by al Qaeda-linked Nusra Front. (Reporting by Humeyra Pamuk and Tulay Karadeniz; Writing by Nick Tattersall; Editing by Alison Williams)