BRUSSELS/KASTANIES (Greece) • European Union member states have stood squarely behind Greece as it steps up efforts to secure its frontier against migrants arriving from Turkey, taking measures including a week-long shipping ban around its Aegean islands.

In a statement agreed by European interior ministers meeting in Brussels on Wednesday, the 27 capitals rejected what they said is Turkey's use of desperate migrants to pressure its neighbours, saying the "situation at the EU's external borders is not acceptable".

Thousands of migrants have made for Greece since Ankara said on Feb 28 that it would let migrants cross its borders into Europe, reneging on a 2016 deal in which Brussels agreed to pay billions of euros in exchange for Turkey preventing migrants from crossing over.

Ankara wants Brussels to step up support for the 3.7 million refugees and migrants that Turkey is already hosting, and back Turkey in its increasingly intense confrontation with the Syrian regime.

But EU members insist Turkey must stick to the deal, with the statement saying it "strongly rejects Turkey's use of migratory pressure for political purposes".

The EU backing for Greece came despite a warning by the United Nations that Greece's suspension of asylum claims has no legal basis.

Greece has repulsed nearly 35,000 migrants trying to cross into its territory illegally since Turkey opened its border, government sources said.

Yesterday, it banned vessels from sailing around its Aegean islands of Chios, Lesbos and Samos, which are close to the Turkish coast and a regular target for dinghies packed with migrants trying to enter the EU. The ban which runs until March 12 exempts merchant ships, Nato patrol vessels, as well as those from the EU's border agency Frontex.

Lesbos already hosts more than 20,000 asylum seekers, many of them living in filthy conditions in overcrowded camps.

Athens has accused Turkish forces of helping the migrants - many of whom are from Afghanistan and Pakistan as well as Syria and other Arab nations - to cross the border.

Turkish Interior Minister Suleyman Soylu visited Edirne province bordering Greece yesterday and announced the deployment of 1,000 special police to the area to halt the pushback of migrants towards its territory.

Meanwhile, EU leaders were yesterday watching closely a meeting between Turkish President Recep Tayyip Erdogan and Russian President Vladimir Putin in Moscow. The meeting is aimed at defusing the crisis in Syria after a surge in fighting raised fears of their armies clashing, triggering a new migrant crisis for the EU.

Mr Erdogan said before arriving in Moscow that he would be looking for Mr Putin to agree to a rapid ceasefire in Syria's Idlib province, where Ankara is battling Moscow-backed regime forces.

"The measures and appropriate decisions we will take here will calm the region and our two countries," Mr Erdogan told Mr Putin.

Mr Putin expressed his condolences for the deaths of Turkish soldiers in Syria, where dozens have been killed in recent weeks, but he also pointed out that the Syrian army had "unfortunately... suffered serious losses".

"We need to talk about everything, so that nothing like this happens again and it does not destroy Russian-Turkish relations, which I know you also value," Mr Putin said.

AGENCE FRANCE-PRESSE, REUTERS