New Year's eve festivities are likely to be subdued across several countries on Thursday given the looming threat of terror attacks, especially in the major cities. 

Intelligence alerts and a security scare following the 13 November Paris attacks have led to authorities either clamping down on fireworks and festivities or amping up security at year-end gatherings at popular locations. 

The measures come as police across several cities foiled New Year terror plots in the recent days and suspect more threats. 

Terror threats for New Year's eve have put authorities on alert across cities spanning east to west, from New York to London and Brussels, all the way to Delhi and Moscow. 

Earlier this week, Belgian police arrested two people for plotting to carry out terror strikes at symbolic locations in Brussels on 31 December. The police also recovered Isis propaganda material in the raids. 

The terror threats led to the cancellation of New Year fireworks and festivities in Brussels, Belgium's capital. 

On Wednesday, Turkey arrested two Isis suspects in Ankara who had plotted to carry out attacks during New Year celebrations.

In India, intelligence agencies have warned that  20 Lashkar-e-Taiba (LeT) terrorists have entered from Pakistan to carry out terror attacks on New Year's eve

The Parliament building, the army headquarters and Indian Prime Minister Narendra Modi himself were said to be on the radar of the LeT terrorists, reports said.

Indian security forces conducted mock drills in Delhi on Tuesday night to prepare for threats on New Year's eve.

Meanwhile, United States President Barack Obama was briefed on terror threats in the three US cities of New York, Los Angeles and Washington during the year-end celebrations. 

New York City police will deploy 6,000 personnel at Times Square on New Year's eve, which will be the biggest such police deployment in the area ever, according to CNN

Russia, too is on alert for terror threats, and Moscow announced that Red Square will be closed for New Year celebrations due to security reasons, which is said to be the first such occurrence. 

There is also a high alert in London ahead of the New Year, following intelligence alerts of a possible  gun or bomb attack at crowded places, The Telegraph had reported. 

Security has also been stepped up in several regions in Indonesia after nine terrorists were arrested last week, some linked to the Islamic State, who were allegedly planning terror attacks in Jakarta.