Four people have been arrested in the Paris region and France's interior minister says there were fears that they were planning an attack.

Few details were available on the Wednesday morning arrests. French Interior Minister Bernard Cazeneuve said the four were taken in for questioning, including one man under house arrest who was suspected to be in contact with Islamic State extremists.

Judicial and police officials, who requested anonymity to discuss the detentions, said one of the four was a woman, all were born in France and they were between 21 and 30 years old. A subsequent search found an unused Kalashnikov cartridge, SIM cards, USB cards and a gun for firing blanks.

Tensions are high in France since the Nov. 13 attacks in Paris that left 130 people dead.