SOFIA (Reuters) - Bulgaria’s Interior Ministry said on Saturday it had suspended 13 border officers over accusations that dozens of people arriving from France this week had passed through passport control at Sofia airport without having documents checked.

The action follows calls from Prime Minister Boyko Borissov for stern punishment over the March 20 incident that highlights challenges Bulgaria faces in convincing the European Union that it is addressing shortfalls in applying the rule of law.

Bulgaria, an EU member since 2007 and holder since January of the six-month EU presidency for the first time, has had its application to join the EU’s Schengen free-movement area rejected.

EU officials have said the government has not done enough to tackle organized crime, corruption and security shortcomings.

Interior Minister Valentin Radev said the border officers could be sacked or face disciplinary sanctions, depending on the outcome of the investigation.

Of the 13, seven officers were part of a team on a shift at the airport who left their posts for about 15 minutes, allowing about 40 passengers flying in from Paris to pass through without having their passport checks.

“It is good that the flight was from Paris,” Radev told reporters. “Passengers had been already checked at a European airport and this guarantees no terrorists have entered.”