ISTANBUL (AFP) - Turkey has detained a Japanese citizen in the south of the country on suspicion of seeking to cross the border into Syria to join Islamic State (IS) militants, the Dogan news agency said on Wednesday.

The young man aged 24, named as M.M., was detained late on Tuesday in the Nizip district of the southern city of Gaziantep, close to the Syrian border.

According to Dogan, he had admitted to wanting to travel to Syria after getting to know an unnamed contact by telephone and then agreeing the cross the frontier.

He will be deported from Turkey back to Japan once the investigation is completed, the agency added.

It said he was detained during a routine check by the Turkish gendarmerie while being driven towards the border settlement of Karkamis.

The official Anatolia news agency said police had confirmed his contacts with militants by examining messages on his mobile phone.

Long accused of not doing enough to police its border with Syria, Turkey has in the last months tightened controls, detaining dozens of foreign militants.

The arrest of a Japanese citizen is hugely unusual, as most of those detained seeking to cross the border come from countries with large Muslim populations.

Images published by Dogan showed the bespectacled young man kneeling in the middle of the road with his hands above his head, guarded by an armed soldier.

Turkish officials said security forces on Tuesday arrested 10 suspected Islamic State (IS) members at the Syrian border in the Gaziantep region, including a would-be suicide bomber. Their nationalities were not disclosed.

Turkey is on high security alert after three Israelis and an Iranian were killed when a suicide bomber suspected to be affiliated with IS blew himself up on Istanbul's most famous shopping street on Saturday.

A radical offshoot of the outlawed Kurdistan Workers Party (PKK) meanwhile claimed a bombing in Ankara earlier this month that left 36 dead.