The UN’s refugee agency UNHCR has criticised Greece over reports that it has been denying entry to migrants and asylum seekers who reach its borders.

UNHCR chief Filippo Grandi said in a statement that there had been deaths among the migrants seeking asylum.

“Those seeking protection have been met with violence, ill-treatment and pushback at multiple EU ports of entry, resulting in the loss of lives, Mr Grandi said.

He said UNHCR was “alarmed” by the almost 540 reported incidents of informal returns by Greece authorities starting in 2020.

Mr Grandi said there had also been disturbing incidents reported in central and south-eastern Europe at the borders of EU member states.

“People report being left adrift in life rafts or sometimes even forced directly into the water, showing a callous lack of regard for human life,” Mr Grandi said.

He said at last three people are reported to have died after being abandoned in rafts in the Aegean Sea since September.

“Equally horrific practices are frequently reported at land borders, with consistent testimonies of people being stripped and brutally pushed back in harsh weather conditions,” he said.

The accusations follow a study by UNHCR which interviewed thousands of people across Europe and which found “a disturbing pattern of threats, intimidation, violence and humiliation”.

Mr Grandi called for what he termed a “legally and morally unacceptable practice” to stop.

“The right to seek asylum is not dependent upon one’s mode of arrival. And we fear that these deplorable acts are now becoming normalised and part of nations’ policies,” he said.

“States must uphold their commitments and respect fundamental human rights, including the right to life and right to asylum.

“How Europe chooses to protect asylum-seeks and refugees matters and is precedent-setting not only in the region but also globally,” he said.

The Greek government expressed “surprise” at Mr Grandi’s comments.

“Greece protects the external borders of the European Union, in total compliance with international law and in full respect of the charter of fundamental rights,” the Greek immigration department said in a statement.

“Our national independent authorities investigate all claims of alleged breaches and we proactively call for evidence to be provided,” the statement said.

Greece says that that Turkey is not a country at war and said it has an obligation under the 2016 EU-Turkey agreement to prevent illegal departures of migrants and accept their return.

The statement said that since 2015, Greece has rescued more than 230,000 nationals from third countries at sea.

“Ultimately, Greece cannot solve the migration crisis alone, we still urgently need more tangible support and greater commitment at an EU level and from member states, particularly with relocations,” the statement said.