Eight people are being held hostage in a supermarket in the town of Trebes southwestern France on Friday by a gunman, who claimed allegiance to the ISIS terrorist group. A police source said that the hostage-taker had shot at a police officer. The mayor of Trebes announced that two people were shot in the incident. Their condition is still not known. The man "entered the Super U supermarket at around 11.15 am and shots were heard," a security source told AFP on condition of anonymity. A source at the Paris prosecutors office said counter-terrorism prosecutors were investigating the hostage-taking. Separately, the UNSA police union said on Twitter a police operation was underway after an individual had earlier shot at four officers in the Carcassone region injuring one of them. It was unclear if the two incidents were linked.