(Adds border security tightened, poll on military deployment)
BERLIN, Nov 20 (Reuters) - Germany's top prosecutor is investigating whether an Algerian man detained at a refugee centre last week knew in advance about the Paris attacks but failed to tell the authorities, officials said on Friday.
Staff were looking into allegations the man told Syrian refugees in the western town of Arnsberg that fear and terror would be spread in the French capital, the federal public prosecutor's office said.
"We've taken the lead in the investigation ... Further investigation will show if the accusations are really true," a spokesman for the federal prosecutor added.
Local prosecutors initially looked into the alleged comments. The decision by the federal public prosecutor to take the lead could suggest that authorities are taking the accusations more seriously.
The interior minister for the state of North Rhine-Westphalia, where Arnsberg is located, said on Thursday that the suspect was still in custody and refusing to talk. "The accused is not cooperative," Ralf Jaeger said.
The German government has increased security measures since the attacks in Paris on Friday last week.
Interior Minister Thomas de Maiziere said a further 150 police will be sent to the border with Austria to reinforce a 1,500-strong force there. Virtually all migrants enter Germany from Austria.
Since the beginning of the year, more than 900,000 new arrivals have been registered across Germany, a spokesman for Bavarian Interior Minister Joachim Herrmann said.
An opinion poll published on Friday found that 91 percent of Germans supported tighter security measures after the Paris attacks.
Germans were more divided over whether their armed forces should participate directly in combat missions against Islamic State militants in Syria and Iraq.
About 52 percent said they were against the idea while 41 percent supported it, according to the survey by pollsters Infratest dimap for broadcaster ARD.
Germany is helping to train Kurdish security forces in Iraq but has not joined the United States and France in air strikes against Islamic State positions in Syria. (Reporting by Michael Nienaber and Joseph Nasr; Editing by Andrew Heavens)
Our Standards: The Thomson Reuters Trust Principles.