Updated at 11:05 a.m. ET
A pair of gunmen attacked a tourist hotel on the popular Tunisian beachfront resort of Sousse, killing at least 28 people, including British, German and Belgian tourists, according to the North African country's health ministry.
The Health Ministry said 36 were wounded in the attack.
The Associated Press quotes Interior Ministry spokesman Mohammed Ali Aroui as saying Tunisian security forces had killed one of the attackers and that the other had fled the scene.
Aroui said a police operation to apprehend the second gunman was ongoing and that exchanges of gunfire were continuing.
He said that the gunmen "infiltrated the buildings from the back before opening fire on the residents of the hotel, including foreigners and Tunisians," according to AP.
The AP said there were no details of the nationalities of those killed.
British tourist Gary Pine tells Sky News that he was on the beach when he heard what he and others thought was firecrackers going off nearby.
"There was a mass exodus off the beach," he said, as reported by the AP.
Pine said guests at his hotel were first told to lock themselves in their rooms and later, to gather in the lobby.
The attack in Tunisia follows another attack in southern France on a gas factory, where one person was found beheaded and a flag of the self-declared Islamic State was found. Twelve others were wounded.
British Prime Minister David Cameron said an emergency response committee would meet later today to discuss the attacks in France and Tunisia.
"This is a threat that faces all of us, these events that have taken place today in Tunisia and in France, but they can happen anywhere — we all face this threat," he was quoted by Reuters as telling reporters.