Authorities in Greece expressed concern Monday that migrants and refugees are gathering on Turkey's coast with plans to cross the Aegean Sea to Greek islands despite movement restrictions in both countries to prevent the spread of the coronavirus.

Daily clashes between border police and asylum-seekers broke out at the land border between Turkey and Greece in March after the Turkish government said it would no longer stop people from trying to enter Europe.

Greek government spokesman Stelios Petsas said authorities now “have seen signs of activity" on the shores of Turkey.

A riot policeman wearing a face mask guards as migrants wait in a queue to board a ferry at the port of Mytilene, on the northeastern Aegean island of Lesbos, Greece, Friday, March 20, 2020. The ferry boat is carrying to a mainland detention center some 600 people who reached Greece's eastern Aegean Sea islands of Chios, Lesbos and Samos in recent days, after neighboring Turkey said it would no longer stop migrants on its territory from heading towards European Union member-state Greece. That move prompted a border crisis between the two historic regional rivals. (AP PhotoVangelis Papantonis)

A riot policeman wearing a face mask guards as migrants wait in a queue to board a ferry at the port of Mytilene, on the northeastern Aegean island of Lesbos, Greece, Friday, March 20, 2020. The ferry boat is carrying to a mainland detention center some 600 people who reached Greece's eastern Aegean Sea islands of Chios, Lesbos and Samos in recent days, after neighboring Turkey said it would no longer stop migrants on its territory from heading towards European Union member-state Greece. That move prompted a border crisis between the two historic regional rivals. (AP PhotoVangelis Papantonis)

“We will ... continue to do whatever it takes to defend our sovereign rights and guard the borders of Greece and Europe," he said.

The Greek islands last year were the European Union’s busiest entry point for illegal migration, according to European border agency Frontex.

Turkish authorities previously inhibited migration to Europe in return for Syrian refugee aid as part of a deal with the EU.

Migrants wait in a queue to board a ferry at the port of Mytilene, on the northeastern Aegean island of Lesbos, Greece, Friday, March 20, 2020. The ferry boat is carrying to a mainland detention center some 600 people who reached Greece's eastern Aegean Sea islands of Chios, Lesbos and Samos in recent days, after neighboring Turkey said it would no longer stop migrants on its territory from heading towards European Union member-state Greece. That move prompted a border crisis between the two historic regional rivals. (AP PhotoVangelis Papantonis)

Migrants wait in a queue to board a ferry at the port of Mytilene, on the northeastern Aegean island of Lesbos, Greece, Friday, March 20, 2020. The ferry boat is carrying to a mainland detention center some 600 people who reached Greece's eastern Aegean Sea islands of Chios, Lesbos and Samos in recent days, after neighboring Turkey said it would no longer stop migrants on its territory from heading towards European Union member-state Greece. That move prompted a border crisis between the two historic regional rivals. (AP PhotoVangelis Papantonis)

Greek Defense Ministry officials said military personnel have been guarding the country's land and sea borders since Turkey accused the EU of not abiding by its commitments and said it would no longer deter people headed to Europe.

A migrant adjust his tent in the village of Petra on the northeastern Aegean island of Lesbos, Greece, Friday, March 27, 2020.  Some 56 migrants who reached Lesbos in smugglers' boats from Turkey over the past few days have been quarantined in small tents in Petra for the past three days. Under public health measures adopted to hinder the spread of the new coronavirus, Greece places all people arriving from abroad in two-week quarantine. Lesbos' main migrant facility, near the village of Moria, is crammed with about 20,000 people even though it was built for 2,700. (AP PhotoPanagiotis Balaskas)

A migrant adjust his tent in the village of Petra on the northeastern Aegean island of Lesbos, Greece, Friday, March 27, 2020. Some 56 migrants who reached Lesbos in smugglers' boats from Turkey over the past few days have been quarantined in small tents in Petra for the past three days. Under public health measures adopted to hinder the spread of the new coronavirus, Greece places all people arriving from abroad in two-week quarantine. Lesbos' main migrant facility, near the village of Moria, is crammed with about 20,000 people even though it was built for 2,700. (AP PhotoPanagiotis Balaskas)