A 33-year-old Moroccan went on trial in Duesseldorf on Monday on allegations hesexually assaulted a woman on New Year's Eve, one of a string of attacks that night blamed largely on foreigners that fueled a nationwide debate over immigration policies.

The defendant, identified only as Toufik M. in line with German privacy rules, is accused of being part of a group of 15-20 men who surrounded the woman and groped her. No pleas are entered under the German system.

The woman who filed the complaint, described only as an 18-year-old from nearby Moenchengladbach, testified that the defendant lifted her skirt and grabbed her buttocks, while others groped her elsewhere in an attack that lasted about three minutes, the dpa news agency reported.

"They grabbed me everywhere and held me," she testified. "The worst was not knowing what was going to happen."

The defendant's 16-year-old girlfriend told the court, however, that he had been with her all night at a club, but refused to identify any friends or other witnesses who could corroborate that he was there.

It is the first sexual assault case related to New Year's Eve attacks to go to trial. Most attacks are alleged to have occurred in Cologne, about 50 kilometers (30 miles) south of Duesseldorf.

Through the end of March, police in Cologne received 1,527 criminal complaints, with more than 500 victims alleging sexual crimes. Authorities have described the suspects as predominantly Arab and North African men.

In Cologne, three people have already been convicted of thefts, and a 26-year-old Algerian was charged last month with groping a woman. No trial date has yet been set for him.

In the Duesseldorf case, police were able to bring charges after the 18-year-old victim recognized the defendant in a television documentary on street crime in the city aired Jan. 31.

Spiegel TV, which made the documentary, said Toufik M. moved to Duesseldorf two years ago after spending many years in Milan, Italy, and had applied for asylum in Germany.

He had previously been investigated 20 times for various crimes, including causing bodily harm and theft, and was once sentenced to seven months' probation, Spiegel reported.

Toufik M. told the program he had stolen items — "sometimes a pair of pants or a cellphone"— but "only to be able to be able to buy something to eat."

Amid outrage over the Cologne crimes, the German government has moved to make it easier to deport foreign criminals. The changes, which went into effect last month, mean that even a suspended prison sentence would be grounds for deportation if someone is found guilty of crimes including bodily harm,sexual assault, violent theft or serial shoplifting.