Story highlights

NEW: All six who were detained for questioning in Belgium have been released, official says

Munich officials clear out two train stations over terror concerns

New York police, FBI step up security for New Year's Eve

CNN  — 

Disrupted terrorist plots. Increased police presence. Warnings to stay alert.

Fears of terrorism and stepped-up security provide a sobering backdrop to planned New Year’s Eve celebrations around the world.

In the United States, federal and local security officials are tightening security in high-profile locations, including New York’s Times Square and the Rose Bowl festivities near Los Angeles. In Belgium and Turkey, police said they disrupted terrorist plots that would have targeted celebrations to ring in the New Year in the capitals of those countries.

Here’s a look at the latest news on that front around the world:

Germany

As midnight approached, police in Munich cited serious concerns about a possible terror attack in telling resident to stay away from crowds and large gatherings. Authorities shut down the main train station and one in the western district of Pasing.

Trains in and out of those stations were canceled.

Police “received concrete information that strongly indicates that there are possible plans for terror attacks in Munich (on New Year’s Eve),” a spokesman told CNN.

United States

Before President Barack Obama left for his Hawaii vacation, his top security officials briefed him about a threat, originating from overseas, of possible attacks in New York, Los Angeles and Washington between the Christmas and New Year’s holidays, according to senior U.S. officials briefed on the matter.

The officials said the threat was uncorroborated and was based on a single source, and it didn’t mention specific locations in the cities. But they said they are always concerned about “soft targets” such as large gatherings and mass transit systems.

In the wake of attacks in Paris, San Bernardino, California, and elsewhere, the FBI is boosting the number of agents and staff in some of its 24-hour command centers around the country, including in New York, Washington and Los Angeles.

About 6,000 police officers will fan out around Times Square for the annual New Year’s Eve celebration there, Police Commissioner Bill Bratton said.

“We are not aware of any threat at this time that we deem credible,” he said.

Among the tools the police will use to guard against would-be criminals or terrorists: cops on helicopters and boats along with hundreds of additional mobile cameras and radiation detectors. It’s a grim reminder of the threats posed by terrorist organizations from around the world. In addition, hundreds of officers will carry rifles, said James O’Neill, a top police official in New York.

“We are ready,” New York Mayor Bill de Blasio said this week. He called New York “the best prepared city in the country to prevent terrorism and to deal with any event should it occur.”

New York Police Commissioner Bill Bratton, left, and Mayor Bill de Blasio say the city is ready. They're shown in a photo from a few weeks ago.

In the Los Angeles-area city of Pasadena, there will be more cameras watching the route of Friday’s Rose Parade, city Police Chief Phillip Sanchez told reporters.

“It’s not the first year we’ve had cameras, but there will be more of them installed by (the Department of Homeland Security),” Sanchez said.

The additional cameras are part of more resources and money being used for the event and Friday evening’s Rose Bowl football game, which are considered elevated security events for the first time.

Anthony La Berge, a chief in the Los Angeles Sheriff’s Department, said more officers will be at the parade and later at a celebration at Grand Park.

“This is probably largest deployment they’ve ever had,” he said.

Rochester, New York, joined the small number of cities worldwide to cancel New Year’s festivities.

Justice Department officials announced they had thwarted a Rochester man’s plans to kill New Year’s Eve participants in the name of ISIS at an upstate New York bar and restaurant.

Emanuel Lutchman, 25, was charged with attempting to provide material support to ISIS, which carries a possible sentence of up to 20 years in prison and a $250,000 fine.

The city canceled its fireworks show and announced it would add officers in the field.

Belgium

New Year’s festivities in Brussels, including fireworks, were canceled. Mayor Yvan Mayeur cited the nation’s heightened terror alert.

Belgian authorities arrested two people on suspicion of being involved in a plot to attack “emblematic sites” in the nation’s capital during New Year’s celebrations, the federal prosecutor’s office said Tuesday.

The two suspects are members of a Muslim biker gang called the Kamikaze Riders and are suspected to have discussed attacking Brussels’ Grand Place square and other places where crowds gather, as well as police and military facilities, a senior Belgian counterterrorism official told CNN on condition of anonymity.

On Friday, authorities said that the last of six other people who were detained Thursday for questioning in connection with the alleged plot have been released.

Belgian soldiers patrol Tuesday at the Grand Place in Brussels, mentioned as a possible terror target.

The alleged plot appears to have been inspired, but not directed, by ISIS, the counterterrorism official said.

Turkey

Turkish police say they’ve arrested two people with alleged ISIS ties on suspicion of planning a bombing attack in Turkey’s capital on New Year’s Eve.

The two were arrested Wednesday as they allegedly scouted potential attack locations in the capital, Ankara, the Ankara governorship said.

The pair had a vest with explosives and a backpack “ready for use” – with iron marbles and sticks and other materials for use in bomb-making – the governorship said.

Investigators believe the pair intended to target two locations near Ankara’s Kizilay district, the country’s semiofficial Anadolu news agency reported, citing the Ankara chief prosecutor’s office.

On October 10, two bombings outside Ankara’s main train station killed more than 100 people. No group claimed responsibility for that attack, though Turkish officials have blamed ISIS, which captured vast swaths of neighboring Syria and Iraq.

France

The French capital will usher in the new year “without fanfare,” said Paris Mayor Anne Hidalgo, as memories of multiple attacks that left 130 dead in November remain fresh. A planned firework display has been canceled, and celebratory projections on the Arc de Triomphe, which sits at the head of the Champs Elysses, will be shorter than normal.

The thoroughfare will remain open – it is the traditional center of Paris’ new year celebrations – but security will be ramped up to reflect the city’s jitters just weeks after the devastating attacks, which saw football fans and concertgoers targeted by militants with ties to ISIS.

Austria

There is heightened security in Vienna after police there said several European cities were warned of possible terror attacks. The warning did include the names of several possible attackers Vienna police investigated without finding “concrete further results,” authorities in the Austrian capital said Saturday.

Police will initiate more thorough security checks, ensure quick readiness in case of an emergency and increase vigilance in terms of empty suitcases and bags for New Year’s, Vienna police said.

One of the big events on New Year’s Eve is the Hofburg Silver Ball. There are also big outdoor events on Graben Street and in front of city hall.

CNN’s Shen Lu, Kristina Sgueglia, Gul Tuysuz, Nic Robertson, Ram Ramgopal, Steve Almasy, Evan Perez, Shimon Prokupecz, Cheri Mossburg and Jason Kravarik contributed to this report.