Brussels (dpa) - Capital cities across Europe are ramping up security ahead of New Year's Eve celebrations, amid concerns of possible terrorist incidents following last month's deadly attacks in Paris.

Investigators in Belgium announced this week that they had uncovered a plot to target key sites during year-end festivities in Brussels, but other European capitals stressed Wednesday that they had not received any concrete indications that attacks were imminent.

In France, which has been in a state of emergency after 130 people were killed in the November 13 attacks, 60,000 police officers will be on duty during the night of December 31 to January 1.

Paris cancelled its official New Year's fireworks, with private rockets and fireworks generally banned. The areas around the Eiffel Tower and the iconic Champs Elysees boulevard will be barricaded.

In Berlin, several hundred thousand people are expected along a two-kilometre stretch of road leading to the Brandenburg Gate.

The area will be fenced off and patrolled by 900 police officers - 150 more than last year - although a spokesman said there were no indications of specific threats. Sniffer dogs will check the bordering park for traces of explosives.

In Brussels, it remained unclear Wednesday whether the annual fireworks display would take place. The 50,000 people expected at festivities in the centre of town have been advised not to bring bags and to expect police checks.

Other cities are also taking security precautions.

- In London, the police said that around 3,000 officers would patrol the streets over New Year as a precaution, despite a lack of specific threats.

- In Rome, police have been on high alert and more officers have been deployed on the streets for several weeks, a spokesman said. People attending the largest New Year's party, a concert in the Circus Maximus arena, will be screened individually and prevented from taking firecrackers or glass bottles, police said in a statement.

- In Madrid, access will be regulated to the Puerta del Sol (Gate of the Sun), where thousands traditionally see in the new year.

- In Moscow, access to the traditional New Year's party in the Red Square will be restricted to ticket holders.

- In New York, thousands of police officers will be on duty, assisted with helicopters, additional surveillance cameras and chemical and nuclear detectors.

- In Turkey, police arrested two alleged supporters of the Islamic State extremist group who are thought to have planned suicide attacks on New Year's Eve in the capital, Ankara.