The deadly jihadist attacks on Friday from Europe to North Africa and the Middle East may not have been co-ordinated acts – but they very likely were all timed to have maximum impact during the holy Muslim month of Ramadan.

The shooting rampage at two tourist hotels in Tunisia, the suicide bombing of a Shiite mosque in Kuwait, and an attack on an American-owned chemical plant in Lyon, France, that left one victim decapitated, all followed a call issued on Tuesday by the self-proclaimed Islamic State to its followers to turn Ramadan into a time of “calamity for the infidels”.

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While most Muslims observe Ramadan as a period of fasting and reflection, radical Islamists and the Islamic State in particular have focused on Ramadan as a period of intensified jihad, or holy war, when Sunni Muslims should lash out at both non-believers and Shiite Muslims.

“It’s counterintuitive, you’d think [Ramadan] would be a time of turning inward, but for some [extremists] it’s also a time when your holy obligation to fight against the non-believers and blasphemers becomes even more imperative,” says Marvin Weinbaum, a former south Asia intelligence analyst at the State Department who is now a resident scholar at the Middle East Institute in Washington, USA.

“Clearly these acts are planned,” he adds, “and it wouldn’t seem to be simply by coincidence that they occur during a period that increases the fervour that some feel about their religious obligations.”

In a call to arms earlier this week, Islamic State spokesman Abu Mohammed al-Adnani admonished all Muslims and “mujahedeen everywhere” to “embark and hasten toward jihad” and to “rush and go to make Ramadan a month of calamity for the infidels”.

The statement was reminiscent of calls that Al Qaeda in Iraq (AQI), the precursor of the Islamic State, put out to followers during Ramadan at the height of sectarian fighting during the Iraq war.

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In 2007, AQI announced at the outset of Ramadan that it was forming special battalions of “martyrdom seekers” that would “pound the bastions of the crusaders and their renegade tails”. The statement said these “blessed battalions” would “with God’s help … perform their duties in an excellent manner during the month of Ramadan and the enemies of God will suffer a lot”.

American military commanders in Iraq in the years after the 2003 invasion came to gird for spikes in violence – particularly against United States soldiers and Shiite worshippers – during Ramadan.

The belief – or at least the message – of some extremist Islamist groups, in particular the Islamic State, is that those who martyr themselves during the holy month will be particularly blessed in the hereafter.

US and French officials said in the initial hours after the attacks that nothing they had seen suggested that the actions were co-ordinated or linked to statements issued by the Islamic State or any terrorist group.

“Nothing today allows us to go in a direction that [assumes] this is tied to any earlier announced threats,” said Stéphane Le Foll, the French government spokesman, who was in Washington on Friday meeting with administration officials on trade and climate issues.

“We know the threat is always present in France.”

The attacker in France was reported to have waved the black flag of Islamist extremism and to have written in Arabic on his victim.

The attack in France followed the January siege of the Paris offices of the newspaper Charlie Hebdo, and the attack on tourist hotels in Sousse, Tunisia, came weeks after an attack on the Bardo museum in Tunis.

But the bombing of a Shiite mosque in Kuwait appeared to be a tack into new territory for the Islamic State, which claimed the attack and identified the suicide bomber. Kuwait and other nearby, majority-Sunni Gulf states have until now largely escaped the wrath of the Islamic State, although the attack echoed recent Islamic State-claimed bombings of Shiite mosques and quarters in Saudi Arabia.

The Islamic State statement claiming the Kuwait attack said it targeted a “temple of the rejectionists”, referring to Shiite Muslims.

The attack, which took place during the height of Friday prayers, appeared designed to incite sectarian tensions, just as attacks on Shiites during Ramadan in Iraq fed the flames of a sectarian war.

“For the Sunni extremists, the Shiites are not fully Muslim,” says Mr Weinbaum. “What we’re seeing here, as we’ve seen in other cases throughout history, is that sectarian hatred sometimes runs even deeper than it does towards other enemies.”

– Christian Science Monitor