At least 37 people, mostly foreigners, have been killed in an attack on a beach near two tourist hotels in the Tunisian resort town of Sousse, according to the interior ministry.
Officials say one gunman has been shot dead and another is being pursued.
Interior Ministry officials said Tunisians, Britons, Germans and Belgians are among the dead.
In March militants killed 22 people, mainly foreign tourists, in an attack on a museum in the capital Tunis.
Officials say six people have been injured in the attack.
Local media reported that the second attacker had been arrested, but this has not been confirmed. A photo showing the body of the first attacker is circulating on social media.
The attack comes on the same day as, a man was decapitated and several others injured at a factory in France; and after a deadly attack on a Shia mosque in Kuwait.
A British man on holiday told the BBC that he heard the attack on a neighbouring hotel.
From his room, he saw a man with a pistol, but did not know whether this was an attacker or a member of the security forces.
The Hotel Imperial Marhaba was named as one of the hotels close to the attack.
Briton Glenn Leathley told the BBC his daughter had been at the scene and rang him to say “there’s gunfire on the beach”.
Another holidaymaker, Steve Johnson said: “We were just laying on the beach as usual and we heard what we thought at first were fireworks.
“But it was soon pretty obvious that firearms were being discharged and people screaming and to running.”
One image circulating on social media appeared to show a man lying face down in the sand with what looks like blood around his head.
Tunisia has seen militant Islamists gain strength since the overthrow of long-serving ruler Zine al-Abidine Ben Ali in a popular uprising in 2011. — BBC.