ATHENS — Greece on Friday boosted border patrols after Turkey said it would no longer prevent refugees from going to Europe, officials said.

"Greece has tightened the guarding of its borders to the maximum level possible," a government source said.

A police source said border patrols had been doubled and a general call for heightened readiness had been issued.

"Everything is under control, there is no reason for concern," the source said.

"We are monitoring the situation and adapting our forces (accordingly)," another police source said.

An army source said around 300 people had been spotted on the Turkish side of the border in the northeastern Evros region.

"These numbers are not out of the ordinary," the officer said.

A senior Turkish official said earlier Friday that Ankara would no longer close its border gates to refugees who want to go to Europe, shortly after the killing of 33 Turkish soldiers in an air strike in Idlib, northern Syria.

"After developments in Idlib, (Athens) is in close contact with the EU and NATO," the Greek government source said.

An emergency NATO ruling council meeting will be held on Friday over the Syria crisis.

In addition to the asylum-seekers on the land border with Greece, Turkey's private DHA news agency said other migrants had arrived on the coast of Ayvacik in Canakkale, western Turkey, seeking to travel to the Greek island of Lesbos by boats.

AFP reporters on Lesbos said just one boat had arrived with 15 Afghans on board, including several children.

Turkey, which is already home to around 3.6 million Syrian refugees, fears more people arriving in the country where there is growing popular discontent against their presence.

Greece and its EU partners fear another influx of refugees from Syria after more than one million made their way there in 2015 before an EU-Turkey accord was reached on controlling the numbers.

Greece is already struggling to accommodate thousands of asylum-seekers stranded in the country for the past five years, especially on the islands, where migrant camps are stretched far beyond capacity.

More than 38,000 migrants are crowded into camps on the islands of Lesbos, Chios, Samos, Leros and Kos, several times over the official capacity of just 6,200.

Only a few hundred migrants have been sent back to Turkey, and just a handful of European states have offered to accept refugees from Greece after EU borders were shut in 2016.

The conservative government of Prime Minister Kyriakos Mitsotakis, which came to power in July, has failed to persuade Greek island authorities to accept the creation of new camp facilities.

Camps on the Greek mainland are also full, and local authorities there also oppose efforts to relocate additional asylum-seekers.

Earlier this week, the government tried to push forward with its camp plans by sending riot police and construction machinery to Lesbos and Chios.

But after days of violent skirmishes with local protesters that left dozens injured, the police were pulled back on Thursday.

Mitsotakis has announced he will visit Samos, Lesbos and Chios after meeting with local mayors on Thursday in a bid to defuse tension. — AFP