European Union leaders have visited Greece’s border with Turkey to show solidarity with the country as it tries to prevent thousands of migrants from crossing.

It came as the EU pledged €700 million in aid to Greece, and gave more details of a European intervention force to be deployed in the area to help the Greek authorities.

The visit from leaders from the EU’s three main institutions came four days after Turkey stopped trying to prevent migrants, many of them from Syria, from reaching the European Union – prompting clashes with Greek security forces at the border.

“This border is not only a Greek border but it is also a European border. And I stand here today as a European at your side,” Ursula von der Leyen told the Greek Prime Minister Kyriakos Mitsotakis.

“Turkey is not an enemy and people are not just means to reach a goal. We would all do well to remember both in the days to come. I thank Greece for being our European ‘aspida’,” the Commission president added, using the Greek word for “shield”.

Von der Leyen was speaking during a joint news conference also attended by the presidents of the European Council and European Parliament, Charles Michel and David Sassoli, as well as Andrej Plenkovic, prime minister of Croatia which currently holds the EU presidency.

Of the new money offered to Greece, half (€350 million) would be immediately available, while the other half could be requested "as part of an amending budget", the Commission president explained.

The EU's border agency Frontex is preparing a "rapid border intervention" team in response to a Greek request for help. Von der Leyen said this would provide several patrol vessels, aircraft and 100 border guards at Greece's land and sea borders.

Greek PM Kyriakos Mitsotakis (centre) with EU leaders Charles MIchel and Ursula von der Leyen, flying over the Greek-Turkish border, March 3, 2020. (Dimitris Papamitsos/Greek Prime Minister's Office via AP)

'An inhumane response'

Some humanitarian groups have expressed anger at how Greece and Turkey are dealing with the situation at the border, as Greek authorities said they had thwarted another 1,000 attempted border crossings overnight.

"We've seen quite a lot of unhappiness with some of the language that's being used," Euronews correspondent Jack Parrock reported from Brussels, citing von der Leyen's use of the term "shield". "They are concerned that this is language that is not appropriate from the European Union when a lot of the people coming are obviously fleeing wars in Syria and in other places as well".

"What we've seen today is a hard line and an inhumane response. EU leaders today have let Greece off the hook for closing its borders, and off the hook for shutting down the right to asylum for people in need," Eve Geddie, Amnesty International's Deputy Director of Advocacy told Euronews Now.

She said EU leaders had missed an opportunity to show solidarity with migrants. Disputing Turkey's classification as a "safe country", she said the EU should allow people to claim asylum.

"We believe that states have the right and the duty also to control their borders, but we need... to ensure that human rights are also upheld," she added.

Watch our report on the EU leaders' visit and the interview with Amnesty International in the video player above.

Migrant children walking to the Pazarkule border crossing to Greece, wait for food distribution in Turkey, March 3, 2020. (AP Photo/Darko Bandic)

Border crossing attempts continue

Migrants and refugees hoping to enter Greece appeared to be fanning out across a broader swathe of the roughly 200-kilometre-long land border on Tuesday.

Greek authorities said that in the 24 hours between Monday and Tuesday morning, they had prevented a total of 5,183 people from entering Greece, and arrested 45 people, mostly from Afghanistan, Pakistan, Morocco and Bangladesh.

It came after a child died when a small boat capsized at sea off Greece on Monday. The boy, aged around 6 or 7, was among 48 refugees rescued from waters off Mytilene International Airport on the island of Lesbos.

An 'attack by Turkey' on the EU and Greece

Earlier on Tuesday, Austria accused Turkey of blackmailing Europe with the latest migrant crisis, calling it an "attack by Turkey on the European Union and Greece".

"This is now the trial by fire for the European Union whether the external border defence works or not,” Chancellor Sebastian Kurz said in Vienna.

It came as the EU foreign policy chief and other European foreign ministers were meeting Turkish President Recep Tayyip Erdogan in Ankara to find a solution.

“If the external border protection of the European Union doesn't work, then Europe without internal borders is history," Kurz said.

"This is a Turkish campaign. It is an attack by Turkey on the European Union and Greece. People are being abused in order to put pressure on Europe.”

He added: "As the European Union, we mustn't be susceptible to blackmail. If the European Union isn't able to defy President Erdogan then we are not only showing weakness but it's also the beginning of the end.”

Turkey, which agreed on a deal with Brussels to limit the number of EU-bound migrants in 2016, has long threatened to let refugees head for Europe. Ankara accuses Brussels of reneging on the deal and wants the EU to continue funding the hosting of refugees on its territory.

President Erdogan also wants the EU to pressure Russia to stop supporting Syrian government troops. Turkey lifted controls on migrants following the death of over 30 Turkish soldiers in an airstrike in northern Syria.