BRUSSELS (AP) — The Latest on Europe's response to mass migration (all times local):
Austrian Chancellor Werner Faymann is defending his country's decision to build border controls at the main crossing with Italy despite EU criticism.
He says that it is "politically necessary and important to take the needed steps" at the Brenner crossing as long as the control of the EU's outer borders is not guaranteed.
He spoke Tuesday amid expressions of concern about the construction from the European Commission, the EU's executive arm. Commission spokeswoman Natasha Bertaud said that "if these plans should materialize, then we would have to look at them very seriously."
Crews started building barriers, a registration hall and other facilities on the Austrian side of the crossing Tuesday. The work is scheduled to be finished by late May.
Hundreds of migrants and refugees are boarding buses from the impromptu refugee camp on Greece's border with Macedonia and heading to organized camps in northern Greece.
Police said about 350 people on seven buses left Idomeni Tuesday heading to shelters, while a further four buses were to leave later in the afternoon.
More than 11,000 people have been living in Idomeni for weeks after Macedonia shut its border to refugees in early March. The majority live in small tents pitched in fields and along railway tracks, while aid groups have also set up large communal tents. Violent clashes broke out there on Sunday between people attempting to cross the border and Macedonian police.
The Greek government has said it wants to evacuate the sprawling camp in the next weeks.
Danish police warn that migrants attempting to reach Sweden are endangering their lives by trying to cross the rail and motorway bridge and tunnel between the two countries by foot.
Henrik Moeller Jakobsen from the Copenhagen Police says that since February officers have stopped 25 people on foot trying to sneak onto the 12-kilometer (8-mile) link, which is strictly banned for pedestrians.
Moeller Jakobsen said Tuesday that signs warn of the dangers — mainly of being run over by a train — and that controls are so tight accidents are unlikely. The Oresund bridge is used daily by some 75,000 people and is also equipped with CCTV cameras.
In January, Denmark and Sweden tightened border controls, including requiring that everyone traveling between the two countries shows valid travel documents.
Greek police temporarily detained 17 people, mostly foreign nationals, during a crackdown on volunteers suspected of spreading malicious rumors at a restive migrant tent city on the border with Macedonia.
Police said Tuesday that 16 of the detainees were subsequently released without charge, while a German man found carrying a knife was charged with possessing a weapon.
The detainees were identified as German, Austrian, Swedish and Portuguese nationals, as well as two Greeks, a Palestinian resident in Greece and a Syrian.
Greece's left-led government has said some volunteers and charity workers at the Idomeni camp are behind recent riots involving hundreds of migrants and refugees trying to force their way into Macedonia.
About 11,000 refugees and migrants have been stuck for weeks at Idomeni, hoping to move on north through Macedonia.
The European Union says Greece's plan to strengthen its borders to cope with the refugee emergency is not good enough and it has given Athens two weeks to flesh out the details.
The EU demanded that Greece draw up the plan after hundreds of thousands of migrants entered the country, and nations like Germany, Austria, Denmark and Sweden tightened border controls in response.
The Commission said in a statement on Tuesday that "further improvements to the action plan and its implementation are needed in order to comprehensively address the deficiencies identified."
It called on Greece to "provide the additional elements and clarifications by 26 April."
If Athens fails to do so, the Commission is set to recommend that some other countries be allowed to prolong their border controls, possibly until the end of the year.
The Greek government says it sets "immediate priority" on evacuating a sprawling migrant tent city of 11,000 on the border with Macedonia, where clashes broke out with Macedonian police over the weekend.
Spokeswoman Olga Gerovassili also says efforts are intensifying to move people from Piraeus harbor, the country's second-biggest informal migrant camp, to organized shelters.
She said Tuesday more than 1,000 people have left Piraeus, Greece's main port and gateway to the Aegean islands, in recent days. About 3,800 are still living in squalid conditions at the port, down from a high of almost 6,000.
Gerovassili said Greek authorities are in the process of identifying and prosecuting volunteers and charity workers at the border Idomeni camp, whom the government blames for fomenting Sunday's clashes.
More than 53,000 migrants are trapped in Greece.
The European Union's executive arm says it's very concerned about plans by Austria to set up border controls at a main crossing point to Italy over fears of a new migrant influx.
European Commission spokeswoman Natasha Bertaud said Tuesday that "if these plans should materialize, then we would have to look at them very seriously."
Austrian police said that crews were to begin pouring concrete on Tuesday for the foundations of a registration hall, barriers and other structures at the Brenner Pass crossing.
Bertaud said "the Brenner Pass is essential for the freedom of movement within the European Union."
An amateur video that aired on Bulgarian TV appears to show three migrants with their hands tied behind their backs and a group of vigilantes ordering them to return to Turkey.
The migrants, carrying backpacks, are lying on the ground restrained with black zip ties. One of the men surrounding them tells the trio, "No Bulgaria. Go back (to) Turkey," and that they should leave immediately. One of the migrants nods his head to indicate that he understands.
It wasn't immediately clear when the video was shot, but it appears to be in an area near the Bulgaria-Turkey border. It aired on multiple Bulgarian TV stations on Monday, after the video first appeared on social media with a comment reading: "DETENTION OF MIGRANTS AND RETURN TO TURKEY."
The European Union has welcomed in 74 Syrian refugees from Turkey and sent more than 300 migrants back there under a new agreement between the EU and Ankara.
European Migration Commissioner Dimitris Avramopoulos announced the figures to EU lawmakers on Tuesday, and noted that "implementing this agreement is a challenge."
Under the deal, which entered force on April 4, migrants arriving in Greece from Turkey from March 20 who do not qualify for international protection will be sent back.
For every Syrian returned, the EU has pledged to accept one Syrian refugee directly from Turkey, where an estimated 2.7 million Syrians are taking refuge from the conflict in their homeland.
The United Nations and rights groups are concerned the deal might infringe on people's rights.
Turkey's state-run news agency says two more rockets fired from Syria have landed in a Turkish border town, wounding two people.
Anadolu Agency said one of the rockets hit a guesthouse in the town of Kilis on Tuesday while the second landed on an empty field near a bus terminal, wounding two people who were passing by.
Authorities evacuated children from a nearby youth center that has been turned into a temporary school for Syrian refugees, the report said.
Kilis has been hit by cross-border rocket fire in the past week, prompting Turkish artillery units to retaliate in line with the Turkish military's rules of engagement.
The wider province of Kilis borders areas in Syria that are controlled by the Islamic State group, Syrian Kurdish militia or anti-government Syrian rebels.