Greek coastguards have been accused of pushing back migrants and asylum seekers, resulting in dozens of deaths at sea, according to a BBC investigation based on witness statements. While Greece's Maritime Ministry rejects these claims, it says the National Transparency Authority will review the footage obtained by the broadcaster.

European border authorities have been accused for years of using illegal practices such as pushbacks, whereby migrants crossing national border are sent back by force or under threat of force without being able to apply for asylum.

The practice violates a number of international laws, including the Geneva Refugee Convention and the European Convention on Human Rights and EU law, numerous legal experts say.

Here is an overview of the EU countries facing claims of carrying out pushbacks.

One of the main routes that people use to migrate to the European Union is via Turkey into Greece. This puts pressure in Greek border authorities. Media outlets and human rights organizations, meanwhile, have reported numerous violations of international refugee law both in the Aegean Sea between........

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