More than 76,000 migrants left Turkey and headed towards Greece as police erected barbed wire barricades at border crossings and launched tear gas at crowds.

Turkey's Interior minister, Suleyman Soylu, made the claim this morning after Turkey's President Recep Tayyip Erdogan 'opened the doors' on Friday.

Migrants, including an Afghan mother with a five-day-old baby, have waded through the river at Kastanies, on the Greece-Turkey border today, and at least 500 people in seven boats have arrived in Lesbos, Samos and Chios in Greece.

Six migrants were pictured four miles inside the Greek border this morning after they were arrested. Greece, which unlike Turkey is in the EU, is protected by EU border force. 

The EU border force, Frontex, has said it is on 'high alert' and is assisting both Greece and Bulgaria to keep their borders secure. Sofia, which deployed its army to patrol the more than 100-mile frontier, has said there have been no crossings.

Erdogan's decision to re-open the border comes as 34 Turkish troops in Northern Syria were killed by the Russian-backed Assad regime on Thursday. 

There was no immediate criticism of the attack from European allies, but the US said it was concerned. NATO called a meeting at the request of Turkey.