France notified the EU Commission that it would maintain border checks for a further six months despite being one of 26 countries in the Schengen passport-free zone, citing a continuing threat of terror attacks.

France introduced border controls after the Islamic State group attacks that killed 130 people in Paris on November 13, 2015 and has renewed them every six months since then amid new attacks.

“Considering the number of recent and thwarted attacks, particularly the one in Trebes, that have hit French territory, the government has decided a new extension,” the French interior ministry said.

Under Schengen rules, any one of the 26 states that are part of the zone can strengthen border controls for security reasons as they deem necessary.

France reinstated border passport checks after the November 2015 terror attacks in Paris. Such decisions must be renewed every six months. The next deadline for France was April 30.

The extension of border controls follows the deadly terror attack in Trèbes, near Carcassonne, in March in which a terrorist claiming allegiance to so-called Islamic State killed four people and injured 16 others before being shot dead.

Austria is also to extend its border controls for six months, while Germany, Sweden, Denmark and Norway have until May 12 to decide whether to renew their tightened security.

In a letter to the European Commission, Austria’s interior minister Herbert Kickl (FPÖ) asked for a six-month extension of controls on its borders with Hungary and Slovenia.