A man armed with a Kalashnikov rifle gunned down tourists at a beach resort in Tunisia killing at least 37 people.
The ramapge in the resort of Sousse happened at about the same time as a bombing at a Shiite mosque in Kuwait and an attack on a US-owned factory in France that included a beheading. It was unclear if the violence was linked but it came days after the IS militants urged their followers "to make Ramadan a month of calamities for the nonbelievers". In all, at least 65 people were killed.
The attack in Tunisia, the country's worst ever, comes just months after the March 18 assault on the national Bardo museum in Tunis that killed 22 people, again mostly tourists, and has called into question the newly elected government's ability to protect the country.
"Once again, cowardly and traitorous hands have struck Tunisia, targeting its security and that of its children and visitors," President Beji Caid Essebsi said at the RIU Imperial Marhaba hotel, near the beach rampage site.
Mr Essebsi promised "painful but necessary" measures, adding: "No country is safe from terrorism, and we need a global strategy of all democratic countries."
Rafik Chelli, the secretary of state of the Interior Ministry, said the attack was carried out by a young student not previously known to authorities. The shooting spree ended when he was shot dead by police.
The Islamic State group claimed responsibility for the suicide bombing at the Shiite mosque in Kuwait City that killed at least 27 people and wounded scores of other worshippers at midday prayers.
In south-eastern France, a man with ties to Islamic radicals rammed a car into a gas factory, touching off an explosion that injured two people. Authorities arriving at the site discovered the severed head of the driver's employer hanging at the plant entrance.
The suspect, Yassine Salhi, was seized by an alert firefighter, authorities said, and French President Francois Hollande said the attacker's intention had been to cause an explosion. A security alert for the southeast region was raised to its highest level for the next three days.
The attacks were condemned by the United Nations, the US, Israel and others.
"We stand with these nations as they respond to attacks on their soil today," the White House said.
The carnage in Tunisia began on the beach, where tourists described hearing what sounded like fireworks and then running for their lives when they realised it was gunfire. Video of the aftermath showed medics using beach loungers as stretchers to carry away victims.
"He had a parasol in his hand. He went down to put it in the sand and then he took out his Kalashnikov and began shooting wildly," Mr Chelli said.
The gunman then entered the pool area of the Imperial Marhaba hotel before moving into the building, killing people as he went.
The Health Ministry said the 37 dead included Tunisians, British, Germans and Belgians. Another 36 people were wounded.
Since overthrowing its secular dictator in 2011, Tunisia has been plagued by terrorist attacks, although only recently have they targeted the tourism sector.