Three migrants, who are thought to be members of the Al-Nusra Front and a Shia militia, were arrested by Austrian police at asylum homes in Tirol.

The three migrants who were arrested by Austrian police in Tirol are said to have been members of terrorist militia groups in both Iraq and Syria. National Police Director Helmut Tomac said: “The refugees are said to have fought among other militias in Syria and Iraq or helped those that are classified as terrorist organisations in Austria.”

One of the men, a 27-year-old Syrian, is also said to have been involved in the executions of at least 20 soldiers in President Bashar Assad’s Syrian Arab Army, Kronen Zeitung reports.

All three men, a 27-year-old Syrian and two Iraqis aged 19 and 28, were housed in separate asylum homes across the region of Tirol. Peter Oehm, Director of the State Office for Protection of the Constitution, Austria’s domestic intelligence service, said: “The 27- year-old Syrian is suspected of being a member of Jabhat al-Nusra or Kataib Al Farouq in the Syrian civil war between 2011 and 2014 and while fighting the regime shot supporters and troops of Assad.” The Syrian is said to have confessed to killing at least 20 soldiers of the Assad regime and various prisoners in the group’s captivity.

The eldest of the Iraqis captured, according to authorities, is a member of an Iraqi militia group called Al-Hashd al-Shaabi. The militia group, who are funded mostly by Iran, fought against Islamic State forces in Iraq’s northern provinces and were even supported by the government of Iraqi Prime Minister Haider al-Abadi in 2015.

The 19-year-old Iraqi was also a member of Al-Hashd al-Shaabi, and is said to have been involved with aiding the group rather than fighting for them. Neither Iraqi has currently confessed to being a member of the Shia militia, according to Mr. Oehm.

While all three men did sneak into Austria as migrants through Turkey and Greece, police say there is little evidence so far that any were planning terror attacks. The Austrian authorities also noted that so far none of the suspects showed any signs of active terrorist links in Europe or any communication with radical Islamist groups.

The presence of Islamic State members and other terrorists have become an increasing worry for authorities in Europe who recognise that radical jihadists may have infiltrated EU countries during the migrant crisis. Two of the Paris attackers in November came to Europe during the migrant crisis, and multiple fighters from Islamic State have been arrested in migrant homes across the continent.