ATHENS (Reuters) -Greece will deploy two frigates and one more vessel off Libya's territorial waters to deter migrants from arriving at its southern islands of Crete and Gavdos, Greek Prime Minister Kyriakos Mitsotakis said on Monday.

Mitsotakis did not elaborate on the role of the vessels or explain what they would do, but said the move would be in coordination with Libyan authorities and the rest of the European forces operating in the area.

Sea arrivals from northeastern Libya of migrants trying to cross to Europe mainly from the Middle East and North Africa, including war-torn Sudan, have surged in recent months. More than 800 migrants have tried to reach Greece's southern islands since Thursday.

Mitsotakis told Greek President Constantine Tassoulas that the issue was discussed during a national security and defence council on Sunday and that the situation was alarming.

"I have asked the defence minister... to ensure that Greek Navy vessels are deployed off Libya's territorial waters to pre-emptively ... send a message that traffickers will not command who enters our country," he said.

The three ships, including a support vessel would leave Greece in next coming days, two government officials with knowledge of the issue told Reuters.

Greece has been a favoured gateway to the European Union for migrants and refugees from the Middle East, Africa and Asia since 2015 when nearly 1 million people landed on its islands, causing an unprecedented humanitarian crisis. Since then migrant flows from Turkey have dropped significantly.

In more recent years, Greece has seen a rise in arrivals from Libya - including Sudanese nationals fleeing Egypt as well as Egyptian and Bangladeshi nationals - and Athens and Cairo have discussed the spike in migration flows.

Greece and Libya have been trying to mend relations strained by an accord signed in 2019 between the Libyan government and Turkey.

(Reporting by Lefteris Papadimas; Editing by Renee Maltezou and Aidan Lewis)