German police officers will flood the streets of Cologne tonight after 600 women celebrating New Year's Eve were sexually assaulted in the city 12 months ago.

Around 1,800 officers will be deployed this evening - compared to just 140 in 2015 - following the wave of attacks last year.

Terror threats around the world means there will be a heightened security presence in major cities to prevent a similar incident to the Berlin Christmas market attack from happening.

And police will be on patrol in Germany after 1,200 women were sexually assaulted by 2,000 men in a number of cities across the country on New Year's Eve in 2015.

Scroll down for video

Police in Cologne were on guard when people gathered near the city's Cathedral on New Year's Eve

Police officers stand watch in front of Cologne Cathedral, not far from where hundreds of women were sexually assaulted last year

German police officers gather near the Hauptbahnhof before New Year celebrations for 2017 in Cologne, Germany

German Police stand in front of the Cathedral in Cologne, Germany, on New Year's Eve after hundreds of women were attacked in the city

In Cologne, police have installed new video surveillance cameras to monitor the station square after women were attacked nearby last year.

The attacks in the western German city, where police said the suspects were mainly of North African and Arab appearance, fuelled criticism of Chancellor Angela Merkel's decision to accept nearly 900,000 migrants last year.

A leaked police document revealed the bulk of the crimes were committed in Cologne and Hamburg where 600 and 400 sexual assaults on women were reported respectively.

Authorities have therefore increased police presence at hotspots in the major cities, including Cologne.

Other cities where there was a large number of police on the streets included Brussels, Berlin, London and Madrid.

Policemen walk around the main train station on December 31, 2016 during the New Year's Eve celebrations

German police officers carry barriers near the Hauptbahnhof before New Year celebrations for 2017 in Cologne

A security officer carried out a security check in front of the famous Cologne Cathedral on Saturday night

Security guards patrolled the area in front of Cologne Cathedral - one year after 600 women were sexually assaulted on New Year's Eve 12 month ago

The tone of public debate in Germany has become shriller over the past two years with the influx of hundreds of thousands of migrants.

Some Germans blame Merkel for attacks such as the recent rampage in Berlin, where a failed asylum-seeker from Tunisia rammed a truck into a crowded Christmas market, killing 12 people and injuring dozens more.

The German capital has beefed up security after the December 19 carnage, deploying hundreds more police, some armed with machine-guns.

A police spokesman said: 'This year, what's new is that we will place concrete blocks and position heavy armoured vehicles at the entrances.'

Officers in Brussels, Belgium, carried out searches as people attended the New Year's celebrations in the capital

A police officer checks people while controlling access to the centre of Brussels, Belgium

A German police officer patrols the area near the Brandenburg Gate in Berlin, Germany, on New Year's Eve

Armed British police officers stand on duty ahead of the New Year's celebrations, in central London on December 31, 2016