Moria (Greece) (AFP) - Greek officials and UN workers evacuated the first group of what will be hundreds of migrants from the Greek island of Lesbos on Monday, where overcrowding and  sweltering heat have made conditions unbearable.

A first group of 635 Afghans at the Moria camp were transferred early Monday towards the north of Greece, boarding police buses under the supervision of UN refugee agency workers.

"I hope to get out of this hell quickly," 21-year-old Mohamed Akberi, who arrived at the camp five days earlier, told AFP.

The migrants were taken onto a ship, the Caldera Vista, bound for the port of Thessaloniki on mainland Greece.

Another 500 people boarded a second ship, the Aqua Blue, but authorities wanting to fill the boat to capacity delayed its departure until Tuesday.

The transfer follows a decision taken by the Greek government at an emergency meeting Saturday.

The new conservative administration agreed on the emergency transfer of the migrants, prioritising unaccompanied minors and other vulnerable people.

But they also agreed to do away with appeal procedures for asylum seekers to facilitate their swift return to Turkey.

Greece will also step up border patrols with the help of the EU border control agency Frontex. AFP journalists could see regular Greek police boat patrols off the north end of the island, where the landings are most frequent.

Surge of arrivals

Tension has grown between the two countries over the steady flow of migrants arriving on the Greek islands in the Aegean, which lie just off the Turkish coast.

Since the EU signed an agreement with Turkey in March 2016, tighter checks have made access to the Greek islands from Turkey more difficult.

But in recent months, nearly a hundred people on average have managed to make the crossing every day.

The UN High Commissioner for Refugees said that the island of Lesbos was sheltering nearly 11,000 people at the end of August -- four times its capacity.

More than 3,000 people arrived there in August alone, the agency said.

And last Thursday, 13 boats carrying 540 people, 240 of them children, landed at the island -- an unprecedented surge in arrivals that has alarmed the relatively new conservative government.

Fahimeh Nourmohammadi told AFP how she, her husband and two sons had fled Iran to escape religious radicals there.

On Lesbos for the past three weeks, she did not feel safe, she said. "A few days ago a young adolescent was stabbed in the camp," she said.

She wants to get her children, 12 and 16, back in school, she added. "At Moria, my children don't go to school, they are bored and at night they are scared."

"We came all this way so they could have a future, so they could live in a democracy, and not for them to be in an unsanitary camp," she added.

Migrants at the Moria camp have complained that the hygiene conditions are sub-standard and that there are no tents for the new arrivals.

In Brussels, the EU's migration commissioner Dimitris Avramopoulos said the Commission was ready to help Greece in any way it could with the transfers.

The EU remains committed to its 2016 agreement with Turkey and is ready to keep working with Ankara, he added.