German police claim officers stopped hundreds of men who appeared to be of "African descent" in Cologne during New Year's celebrations to prevent another a series of sexual attacks that happened on celebrations on 31 December 2015.

German police forces say the heavy police presence and detentions of men of "African descent" were put in place to prevent the sexual assaults and robberies that struck Germany cities last year during New Year's Eve celebrations. An increase in attacks during the night's celebrations hit at least seven German cities.

In Cologne, around 1,500 officers took to the streets across the city, and detained men who appeared "African" at two train stations to check their identities and question them.

Government documents leaked in July 2016 stated that German authorities believed more than 1,200 women were sexually assaulted on 31 December 2015.

Approximately 600 of the attacks happened in Cologne, and 400 in Hamburg.

Some 2,000 men were believed to be involved in the attacks, which generally began by men surrounding a woman who was then assaulted.

At the time of the assaults Cologne's Chief Prosecutor Ulrich Bremer said that "the overwhelming majority" of attackers were asylum seekers and migrants who had recently arrived in the country.

Only 120 of the 2,000 suspects in the 2015 attacks were identified. Half of those suspects were foreign nationals.

In July, Holger Münch, president of the German Federal Crime Police Office, told the German newspaper Sueddeutsche Zeitung, also said: "There is a connection between the emergence of this phenomenon and the rapid migration in 2015."

On Sunday, 1 January, police in Cologne said it received reports of two sexual assaults. One male suspect was arrested.