Tunisian security forces stand in front of the Imperial Marhaba hotel in the resort town of Sousse after a shooting attack that killed at least 37 people, mostly European tourists. (Fethi Belaid/AFP/Getty Images)

The attacks appeared to have no connection in terms of tactic or target.

The beheading and failed attempt to blow up a chemical plant in France bore no operational resemblance to the suicide bombing of a mosque in Kuwait or the armed assault on a tourist-packed beach in Tunisia.

Even so, the outbreak of violence Friday was seen by counterterrorism officials and experts as part of an emerging pattern — each inspired by, if not directly attributable to, the Islamic State, all somehow fitting into that terrorist group’s chaotic and violent agenda.

U.S. officials and experts said the nearly simultaneous eruptions of violence on three continents are likely to intensify anxieties about the Islamic State’s expanding reach.

The group is still seen as primarily focused on its regional ambitions in Iraq and Syria, where the Islamic State has maintained its grip on large tracts of territory despite recent military setbacks. U.S. officials have said that the organization seems far less driven to launch elaborate, overseas terrorist plots than al-Qaeda and its affiliates.

But the Islamic State is also increasingly seen as the center of an expanding movement whose disparate elements range from the ranks of stray followers drawn by the group’s brand of extreme brutality to formal franchises in Libya and other countries where security has deteriorated.

“It’s become more diffuse geographically and dispersed ideologically,” said Bruce Hoffman, a terrorism expert at Georgetown University. In some ways, Hoffman said, the amorphous nature of that network may make it more difficult to contain than al-Qaeda, which has often exerted an almost corporate-style control of regional franchises and terrorist plots.

U.S. officials said Friday that it was too early to determine whether the attacks were coordinated by the Islamic State, which is also known as ISIS or ISIL.

“While we’re still working to determine whether the attacks were coordinated or directed by ISIL, they bear the hallmarks that have defined ISIL’s violent ideology,” a U.S. official said.

The suspect in France reportedly told authorities of his ties to the Islamic State, and a decapitated corpse has become one of the group’s grisly signatures.

The organization claimed responsibility for the attack in Tunisia, where at least 39 people were killed. Tunisia has been previously targeted in similar attacks by the Islamic State, which has drawn hundreds of recruits from that country.

The mosque bombing in Kuwait was quickly claimed by an Islamic State affiliate.

U.S. officials and counterterrorism experts noted that all three incidents took place just days after a spokesman for the Islamic State urged followers to launch attacks during the month-long Muslim holiday Ramadan, and that the terrorist group may be seeking to mark the anniversary of its declaration of a caliphate in Iraq and Syria.

“With the three attacks, you basically have three different agendas at work at the same time,” said Will McCants, an expert on militant Islamism at the Brookings Institution. “But what’s holding them together are people who are favorably disposed to the broader agenda of the Islamic State.”

A North African intelligence official said the geographically dispersed violence is also a signal to al-Qaeda, its rival for influence among jihadists. “The message is: We can reach anywhere,” the official said.

Given the volume of fighters flowing into and out of Syria, as well as the proliferation of Islamic State propaganda online, “treating this as a counter-radicalization problem on an individual basis is . . . just going to exhaust us,” Hoffman said. “Until the organization is weakened, I don’t think its appeal will be diminished.”

The Islamic State has since its inception threatened to hit Western targets, but its most recent incitements have been more direct and urgent. The group’s principal spokesman, Abu Mohammed al-Adnani, released a recorded statement this past week calling for attacks by followers beyond Syria during the Islamic holy month.

“You all must rush to it and be keen on waging invasion in this eminent month, and commit martyrdom in it,” the message said, according to a translation by the SITE Intelligence Group, which monitors Islamist postings online.

The group asserted responsibility in May for a thwarted attack in Garland, Tex., on an event where cartoonists were drawing the prophet Muhammad.

The targets of Friday’s attacks reflect the broad range of the Islamic State’s goals.

Tunisia has been a particular focal point for the group, in part because the country has made more progress toward democratic political overhauls than other nations in the Middle East and North Africa swept up in the Arab Spring. Tunisia has also seen more than 3,000 of its citizens travel to Syria to fight in that country’s civil war, many of them joining the ranks of the Islamic State.

Tunisia’s democratic overhauls are “bad news for extremists, and therefore I think it is no accident that Tunisia would be a special focus,” said Paul Pillar, former deputy director of the CIA’s Counterterrorism Center.

The Islamic State claimed responsibility for an assault in March on a prominent museum in Tunis where more than 20 people, many of them Western tourists, were killed.

The attack on the American-owned chemical plant in France would fit the Islamic State’s aim of striking Western targets in retaliation for airstrikes by the United States and its allies, as well as sowing anxiety and preoccupying European security services.

The suicide bombing in Kuwait appeared to be part of a broader campaign by the Islamic State to ignite sectarian conflict with followers of the rival sect of Shiite Islam. The attack looked to have been carried out by an Islamic State affiliate known as the Najd Province, a group that has sought to establish a stronghold on the Arabian Peninsula where al-Qaeda’s most potent franchise is based.

Islamic State fighters celebrated the attacks in social media boasts on Friday. One posting on Twitter was addressed to “Christians planning their summer vacations in Tunisia,” and said, “we can’t accept u in our land while your jets keep killing our Muslim brothers.”

But even as U.S. intelligence analysts sought to assess the Islamic State’s role in the three attacks, the group’s carnage in Syria and Iraq continued. Reports from Kobane, Syria, indicated that the Islamic State had killed at least 146 civilians, more than double the death toll in Kuwait, France and Tunisia.

Souad Mekhennet in London and Julie Tate in Washington contributed to this report.