Police in five European countries on Tuesday launched a major crackdown on people-smuggling, making a string of arrests, German authorities said. Officers staged dawn raids in Belgium, Britain, France, the Netherlands and Germany, said police in the northwestern German city of Osnabrueck, considered a hub for the traffickers. Some 900 police were deployed in Germany alone, carrying out searches of 36 sites and arresting 18 suspects in an operation coordinated by Europol and European Union judicial agency Eurojust, they said in a statement. A police spokesman declined to provide further details but French judicial sources said the ringleaders were believed to be based in Iraq, Afghanistan and Eritrea. Germany’s Der Spiegel magazine reported that the operation targeted organised groups taking migrants to England. It quoted Osnabrueck police as saying that the network had smuggled up to 10,000 people via the Channel in the last 12 to 18 months in a highly lucrative scheme. Iraqi-Kurdish suspects were targeted in Osnabrueck, with several warehouses and private addresses being searched. Special forces were deployed because the suspects were believed to be “armed and dangerous”, Der Spiegel reported. The coordinated action with Britain comes amid growing tensions between London and the EU following Brexit. Ties are particularly strained with France over migration. Now Britain has left the European Union, it no longer has a migrant returns treaty with the 27-nation bloc. Britain has repeatedly accused the French authorities of not doing enough to stop the crossings. Despite promises of more cooperation, the number of migrants seeking to cross the Channel from France to England surged in the first half of this year, according to the French interior ministry.