World leaders condemn overnight terror attacks in France, Kuwait, Tunisia

US and UN leaders led an international chorus of outrage and condemnation after a string of suspected Islamist attacks in France, Kuwait and Tunisia Friday left dozens dead.

The White House expressed solidarity and vowed to "fight the scourge of terrorism," offering all three countries "any necessary support".

Aides said US President Barack Obama was being regularly briefed on the attacks, which spanned continents and happened during the Muslim day of prayer in the holy month of Ramadan.

UN Secretary-General Ban Ki-moon also strongly condemned the "appalling" attacks and said those responsible "must be swiftly brought to justice."

While there were no indications that the attacks were coordinated they came days after the Islamic State (IS) group urged supporters to carry out Ramadan attacks.

One person was found decapitated at a gas factory in southeastern France while in Tunisia gunmen killed at least 37 people at a beach resort frequented by European tourists. At least five British tourists were among the victims.

Another 25 people died in a suicide bombing claimed by Islamic State jihadists in Kuwait.

The word "heinous" was repeated time and again as politicians worldwide reacted to the attacks.

European leaders also condemned the "heinous" attacks, vowing to maintain a united front against "barbarism".

French President Francois Hollande and his Tunisian counterpart Beji Caid Essebsi expressed their solidarity against the "scourge" of terrorism.

He also announced he was raising the security level to the highest possible in the Lyon region, where the gas factory attack took place.

Among his fellow European Union leaders gathered for a summit in Brussels, Spanish Prime Minister Mariano Rajoy was one of the first to react to news of the attack in France.

"Barbarism will always be confronted by unity among democrats," he wrote in a message on Twitter.

Spain, which shares a border with southwestern France, swiftly raised its terror alert level from medium to high.

German Chancellor Angela Merkel said the attacks "show the challenges we face when it comes to fighting terrorism and Islamist extremism" while Britain's Prime Minister David Cameron called the attacks the fruit of "perverted ideology".

The EU foreign policy chief Federica Mogherini after the summit called for the Arab world and Europe to stay united.

"Arabs, Europeans, Muslims, non-Muslims, we are together, in the same boat," she said.

"The response will be more unity and expressing very clearly, as an alliance of civilisations, that there can be no way in which a religion be misused to tear us apart."

Italy's Prime Minister Matteo Renzi said the attack in France "confirms that beyond the known battle fronts there are small, very well organised groups".

Czech President Milos Zeman described Islamic State as "a cancer," calling for its training camps to be destroyed.

Outside of Europe, Israeli immigration minister Zeev Elkin urged French Jews to flee to the Jewish state.

"Come home! Anti-Semitism is rising, terror is increasing," he warned.

Muslim clerics also condemned that attacks, using some of the strongest language to do so.

A task force against extremism set up by Egypt's mufti, the government's interpreter of Islamic law, said that attacks had done untold damage to the image of Islam "far more than what anyone else has done, whether Muslim or non-Muslim",

Prominent Sunni cleric Yusuf al-Qaradawi suggested that the militants were worse than "beasts".

"Beasts don't kill other animals except for what they need to eat, but some people never get their fill from murder and blood," he wrote on Twitter.

Canadian Prime Minister Stephen Harper said he was "both saddened and angered today to learn of the heinous terrorist attacks".

The Argentinian, Mexican and Brazilian governments were also among those strongly condemning the attack.

EU head Donald Tusk said that the attack in Tunisia affected foreign tourists but also "the security of the whole region and, in the longer term, the security of Europe."

Austrian Foreign Minister Sebastian Kurz went further, speaking of a "struggle between the civilised world and the barbarism of jihadism."