German police have detained three men as they continue a search for a suspected bomb plotter in the eastern city of Chemnitz.
The suspect was identified as Jaber Albakr from Damascus and police urged anyone with information about his whereabouts to come forward.
Police say two people have been arrested in the main station in Chemnitz and another arrested in Fritz Heckert area, but it is not clear how they are related to the inquiry.
Tom Bernhardt, spokesman for the state criminal police, urged caution.
A tweet from Saxony Police said: “The manhunt is under way looking for the suspect. Currently, we do not know where he is and what he’s wearing. Be careful.”
An image released by police showed a dark-haired man wearing a hooded sweatshirt. He was said to have been wearing similar clothes when he was last seen.
Police raided an apartment in the Fritz-Heckert-Gebiet neighbourhood after a tip-off from the domestic intelligence service.
A blast was heard as armed police forced their way inside.
“The explosion heard was an access measure by the police. A relevant person could not be found,” Saxony police said on Twitter.
They later said that “several hundred grams” of explosives was found in the raided apartment and added that they had been forced to evacuate the surrounding area as a precaution.
The luggage of the pair that were detained at the station was seized and is currently being examined by “special forces”, a police statement said.
Focus news magazine reported Albakr was planning an attack on a German airport.
Traces of explosives were found at the scene, according to police.
Focus cited security sources as saying the suspect had come to Germany with Syrian refugees during the past year.
There is a heavy police presence outside the building, with hundreds of officers in the neighbourhood.
“Please remain in your apartments within the cordoned off area and follow the instructions of the police here and on site,” police said.
Islamic State claimed two attacks in Germany in July in which asylum seekers hurt 20 people – on a train near Wuerzburg and at a music festival in Ansbach.