Security is being stepped up in major European cities ahead of New Year celebrations, with officials wary of possible terror plots.
New Year fireworks and festivities have been cancelled in the Belgian capital Brussels because of an alert.
Extra measures will also be in place in cities including Paris, London, Berlin and Moscow.
Meanwhile in Turkey, security services say they have thwarted a major plot to attack celebrations in Ankara.
Earlier this week, Austrian police claimed a "friendly intelligence service" had tipped them off that major European capitals were at risk of being attacked over the holiday period.
Belgian Prime Minister Charles Michel said the Brussels decision had been taken "given information we have received".
Last year 100,000 people turned out in Brussels to welcome in the New Year.
"In these circumstances, we can't check everyone," Brussels Mayor Yvan Mayeur said.
Earlier in the week, police arrested two people suspected of planning attacks during the festive season and seized propaganda for so-called Islamic State (IS) as well as military clothing and computer equipment.
Belgium has been on high alert since the terror attacks of 13 November in Paris. Several of the perpetrators are thought to have been based in Belgium.
On Wednesday, Turkish police arrested two suspected IS members over an alleged plot to attack celebrations in Ankara.
They reportedly entered Turkey from Syria and were planning two separate attacks on crowded areas, the state-run Anadolu news agency reported.
Suicide vests and explosives were found during police raids.
A double suicide bombing killed more than 100 people in Ankara in October. Turkey has blamed IS, but no group has said it carried out the attack.
Security will also be stepped up in Istanbul, with local media reports saying that some officers will be wearing Father Christmas outfits and other disguises to patrol crowds undetected.
In Paris a New Year fireworks display has been abandoned, but the traditional gathering on the Champs-Elysees will take place amid tight security.
Projections on the Arc de Triomphe will be shorter than normal, four giant screens will be placed at intervals to avoid creating tightly packed crowds and the fireworks display has been cancelled.
"We have decided to mark the New Year in a reflective manner and without fanfare," Mayor Anne Hidalgo said.
November's gun and bomb attacks in the city killed 130 people and at least one of the suspected attackers remains on the run.
The US military has said some IS commanders in Iraq and Syria who had links to the Paris attacks and were planning further attacks on the West have died in bombing raids over the past month.
Red Square closed
Security is also being tightened in cities where the authorities say there is no specific intelligence about a possible attack.
Authorities in Moscow will completely close off Red Square, where crowds normally count down to midnight.
In Berlin, backpacks and fireworks will be prohibited and bags searched on the "fan mile" in front of the Brandenburg Gate, which has reportedly been closed off since Christmas.
Up to a million people are expected to attend the celebration.
Berlin's interior minister Frank Henkel encouraged party-goers to not allow fear to sour their celebratory mood.
"Caution is a good counsellor, fear is not," he told broadcaster RBB.
London's Metropolitan Police will deploy 3000 officers in the inner city, including extra armed officers.
More than 100,000 people are expected to watch the Mayor of London's fireworks show, a ticketed event.
"Our plans are purely precautionary and not as a result of any specific intelligence," said a spokesperson.