LONDON — Hopes for a year less defined by threats of international terrorism were dashed Monday by the European law enforcement agency, which warned there is ''every reason'' to expect attacks in Europe.
The European Police Office (Europol) said the Islamic State militant group is becoming increasingly global and will keep attempting lethal attacks on soft targets in Europe, similar to those in Paris that killed 130 people 2½ months ago.
Rob Wainwright, head of Europol, said at a meeting in Amsterdam of interior ministers that the group has ''developed a new combat-style capability to carry out a campaign of large-scale terrorist attacks on a global stage, with a particular focus in Europe.''
In addition to lone-wolf attacks, Europe increasingly faces the prospect of large-scale, organized, mass terror attacks, the agency said in a report.
Wainwright said more than 5,000 EU nationals have been radicalized by fighting with extremists in Iraq and Syria, and many have returned home.
Europol on Monday opened a new European Counter Terrorism Center at its headquarters in The Hague, the Associated Press reported. The unit will have 40 to 50 experts in counterterrorism and foster intelligence-sharing, track foreign fighters and sources of illegal financing and weapons, and assist European Union countries in counterterrorism operations and investigations.
The meeting in Amsterdam was held amid heightened fears of attacks on European capitals similar to the ones in Paris. On Sunday, the Islamic State released a video that featured the Paris attackers and included footage of some of them executing hostages.
''Expect a mujahid to show up to kill you,'' the alleged ringleader of the Nov. 13 Paris attacks, Abdelhamid Abaaoud, said in the video. He was killed in a shootout with police in a Paris suburb days after the attacks.
The video included general threats against Europe but also showed several landmarks in London, raising concerns about possible plans by the Islamic State to strike in Britain.
Abaaoud reportedly had visited Britain last year. Despite having returned from Syria, he entered the country on a ferry without being detected by police. He also took photos of British landmarks. British authorities estimate 800 British extremists have gone to Syria and Iraq. Nearly 400 are believed to have returned, according to the BBC.
British intelligence services, like authorities in other European nations, have interviewed returnees to decide who should be monitored more closely. But London bombings in 2005 showed it is often hard to analyze who could become a threat to national security. Dozens of officers are needed to observe a suspect around the clock, which makes it necessary for intelligence services to constantly reassess their targets.
The beginning of Sunday's propaganda video showed encryption software allegedly used by the terrorists.
Although it has since been pointed out that the encrypted messages shown in the video are probably fakes and technically flawed, the Islamic State's focus on such tools was probably intended to raise even more alarm. Such fears were reflected in the Europol report Monday, which concluded that ''the availability of secure and inherently encrypted appliances'' as well as ''coded language'' could hamper surveillance.
The report singled out France as a main target. It said there is reason to expect that the Islamic State and terrorists inspired by it, as well as other religiously inspired terrorists, will undertake an attack somewhere in Europe again.
The report did not suggest an attack is imminent. But Bernard Cazeneuve, France's interior minister, was quoted as saying that the nation's intelligence services had prevented more than 10 attacks within the past year. France recently extended its state of emergency, imposed after the Nov. 13 attacks.
Cazeneuve said the report was not an attempt to sow fear but ''to look lucidly at reality.''
According to Europol, the Islamic State has a command center that oversees and plans attacks outside Iraq and Syria.
In Europe, most of its terrorist cells are organized locally. Europol said those cells could be recruiting new members in refugee camps, but it did not find any evidence ''that terrorist travelers systematically use the flow of refugees to enter Europe unnoticed.''
The Islamic State is trying to show that it is capable of conducting a series of deadly attacks all over the world, the report concludes.
Europol also said the Islamic State's rise can partly be explained through its recruitment drive in Europe. Rather than using religion as the prime driver of recruitment, social pressure among peer groups could explain the rapid increase in European recruits.
''The attacks will be primarily directed at soft targets, because of the impact it generates,'' the Europol report said.
Both the November Paris attacks and the October bombing of a Russian airliner suggest a shift in ISIS strategy toward going global, it said.
Several independent analysts have suggested that as the Islamic State has increasingly lost ground in Iraq and Syria, including setbacks to a US-led international coalition and the Russian military, it has lashed out at its foes abroad.
ISIS commanders are given tactical freedom depending on local circumstances, the report said. That degree of liberty, it said, makes it more difficult for law enforcement ''to detect such plans and identifying the people involved at an early stage.'' The European Police Office also warned that the Islamic State's rival terror group, Al Qaeda, remains a threat.