Video emerged on Monday of Greek coastguard officers apparently trying to capsize a boat full of refugees at sea, as a crisis mounted over migrants from the Middle East attempting to reach western Europe.

A migrant child was also killed on Monday when the boat they were aboard capsized off the island of Lesbos and a Syrian refugee trying to cross the Greek border was reportedly killed by rubber bullets, underscoring the dangers faced by those attempting make the passage west from Turkey. It is unclear if the child was on the boat seen in the video.

The deaths, alleged abuse at sea and a diplomatic standoff over migrants between Turkey and the European Union follow an attack by forces loyal to the Damascus regime of Bashar al-Assad on Thursday that killed at least 33 Turkish soldiers in northwest Syria in a confrontation at one of a dozen bases controlled by Ankara.

In response to the incident, Turkey allowed thousands of migrants penned up in the country to head towards its EU land and sea borders with Greece and Bulgaria. The move is seen by analysts as both an attempt to put pressure on western powers to help it resolve the Syria crisis, and to distract the Turkish public from the loss of soldiers in a foreign land.

Turkey says it has allowed more than 117,000 migrants to cross into Europe, but Greeks say no more than 1,000 have made it across. Neither figure has been independently verified, and each country has a political interest in fudging the numbers. On Sunday, Greece suspended temporary protection for asylum seekers, citing national security reasons, drawing criticism from campaigners.

"I get that they have some security issues and concerns," said Devon Cone, senior advocate at Refugees International. "But they also have international obligations towards people seeking safety who approach their borders."

Migrants trapped between Turkey and Greece Show all 20 1 /20 Migrants trapped between Turkey and Greece Migrants trapped between Turkey and Greece Migrants from Afghanistan arrive on a dinghy on a beach near the village of Skala Sikamias, after crossing part of the Aegean Sea from Turkey to the island of Lesbos, Greece Reuters Migrants trapped between Turkey and Greece Migrants waiting on the Turkish side of the border AFP via Getty Migrants trapped between Turkey and Greece A migrant woman holding her child sits in a field near the Meric (Evros) River at the Turkish-Greek border EPA Migrants trapped between Turkey and Greece Migrants run to avoid tear gas thrown by Greek police during clashes near the Pazarkule border gate AP Migrants trapped between Turkey and Greece Refugees walk back after a failed attempt to pass the Greek border near the Meric EPA Migrants trapped between Turkey and Greece A child cries as migrants arrive at the village of Skala Sikaminias AP Migrants trapped between Turkey and Greece A migrant runs during clashes with the Greek police AP Migrants trapped between Turkey and Greece Migrants use an inflatable boat as they attempt to enter Greece from Turkey by crossing the Maritsa river, near the Pazarkule border gate in Edirne, Turkey, 29 February 2020 AP Migrants trapped between Turkey and Greece A migrant from Cameroon detained by Greek authorities sits in a room in the village of Marasia AP Migrants trapped between Turkey and Greece Migrants walk towards the Greek border near the Pazarkule border gate in Edirne, Turkey, Saturday, 29 February 2020. AP Migrants trapped between Turkey and Greece A migrant carries his belongings as he walks toward Meritsa river AFP via Getty Migrants trapped between Turkey and Greece Riot police detain a migrant AFP via Getty Migrants trapped between Turkey and Greece Migrants prepare an inflatable boat as they attempt to enter Greece from Turkey by crossing the Maritsa river, near the Pazarkule border gate in Edirne, Turkey, Saturday, Feb. 29, 2020. On February 29 2020, AP Migrants trapped between Turkey and Greece Migrants use an inflatable boat as they attempt to enter Greece from Turkey by crossing the Maritsa river, near the Pazarkule border gate in Edirne, Turkey, 29 February 2020 AP Migrants trapped between Turkey and Greece Migrants walk to the Greek border near the Pazarkule border gate at Edirne, Turkey AP Migrants trapped between Turkey and Greece Migrants walk to the Greek border near the Pazarkule border gate at Edirne, Turkey, Saturday, February 29 2020 AP Migrants trapped between Turkey and Greece Greek border guard use teargas on migrants trying to enter Greece, at Pazarkule border gate, Edirne, Turkey, Saturday, 29 February 2020 AP Migrants trapped between Turkey and Greece Greek border guard use teargas on migrants trying to enter Greece, at Pazarkule border gate, Edirne, Turkey, Saturday, 29 February 2020 AP Migrants trapped between Turkey and Greece Greek border guard use teargas on migrants trying to enter Greece, at Pazarkule border gate, Edirne, Turkey, Saturday, 29 February 2020 AP Migrants trapped between Turkey and Greece Greek border guard use teargas to push back migrants who try to enter Greece AP

The Turkish president Recep Tayyip Erdogan warned on Monday that millions of migrants would soon head to the European border. “Since the moment we opened our borders, the number heading to Europe has reached hundreds of thousands,” he said during an event in Ankara. “This number will be stated in the millions soon.”

The Greek coastguard claimed in a statement that the boat carrying the lost child was overturned off the coast of Lesbos by its occupants in an attempt to draw rescuers, who managed to save all but the child.

A video released by Turkish authorities purportedly showed Greek coastguard officers attacking a boat full of migrants – nearly ramming their vessel, firing warning shots at them, and striking them with a sharp object.

“Greek coastguard officials performed manoeuvres aimed at sinking the rubber boat en route to Greece carrying irregular migrants off the Bodrum district of Mugla province,” a Turkish official said in a note to journalists. “They opened fire afterwards. Later on, irregular migrants in the rubber boat were hit by long sticks used for manoeuvres.”

The migrants were later rescued by the Turkish coastguard, said the official, and it was not clear if the video showed the incident described by the Greeks.

A 22-year-old Syrian man from Aleppo was also reportedly killed Monday after he was allegedly shot with a rubber bullet while trying to cross the Greek frontier by foot, according to Jenan Moussa, a correspondent from pan-Arabic Dubai-based al-Aan news channel.

A Greek government spokesman called reports of a slain refugee at the border “fake news”.

The opening of the Turkish border is seen as an attempt to put pressure on the European Union, which has downgraded Syria to below Libya and Iran on its list of Middle East and North Africa priorities.

Turkish officials accuse the west of abandoning the country to fend for itself as it is flooded with millions of refugees from Syria and faces the prospect of hundreds of thousands more because of the ongoing Russian and Syrian offensive to retake Idlib province from rebels.

Turkey was supposed to curb the flow of migrants and refugees to Europe as part of a €6.6bn (£5.4bn) aid package, but only half the money has been dispersed, owing to EU accounting rules. But the Turks say the allocated funds are not nearly enough to cover the costs of at least 3.6 million Syrians sheltering in the country.

In a speech on Monday, Mr Erdogan demanded that Europe do their fair share for migrants, who are leaving Syria, Iran, and Afghanistan for Europe. “The era of unilateral sacrifice is over,” he said.