In an interview with German broadcaster "ZDF" on Tuesday, Germany's domestic intelligence chief Hans-Georg Maaßen said that authorities received information early last month that the "Islamic State" (IS) militant group was planning to attack train stations or airports in Germany.

Investigators believe that 22-year old Jaber A., who was arrested in Leipzig on Sunday night, intended to bomb a Berlin airport.

"We received intelligence that he initially planned to attack trains in Germany," Maaßen said. "Later, the plans became more specific and directed at airports in Berlin."

The police were tracking Jaber A. and decided to raid his Chemnitz apartment on Friday, when the suspect was seen buying glue in a one-euro-store.

"We have assumed that this might be the last chemical ingredient he needed to make a bomb," Maaßen said.

In the apartment, the police found a highly violatile substance, likely identical with the explosives used by 'IS' for attacks in Paris and Brussels.

The explosives were "almost ready, or even ready for use", state police chief  Joerg Michaelis said at a Dresden press conference.

"From everything we know today, the preparations in Chemnitz are similar to the preparations for the attacks in Paris and Brussels," German Interior Minister Thomas de Maiziere said.

Earlier in the day, Saxon state police confirmed via Facebook that Syrians living in Leipzig had told them that they had apprehended the suspect in an apartment north of the city center. The Facebook post added that police were "very consciously" not giving any more details of the circumstances of the arrest, "because we do not want to provoke any dangers for those persons who gave us the tip."

Michaelis said in the press conference on Monday that a Syrian man walked into a police station with a photo of Jaber A. on his phone, saying that he and his roommates had caught him.

According to the Bild newspaper, Jaber A. had met with three other Syrians while looking for urgent accommodation in Leipzig, after fleeing the police in Chemnitz. His new roommates eventually recognized him and managed to constrain him in their apartment.

Jaber A. had tried to bribe his captors, one of the Syrians who overpowered him told the German RTL broadcaster.

"We told him: You can give us as much as you like, but we are not letting you go," Mohammed A. told the TV station.

The Syrians tried calling the police, but the officials could not understand them. This prompted Mohammed to go to the station and lead the authorities to the suspect.

"I was so angry at him. I won't accept such a thing – especially here in Germany, the country that opened its door to us," he added.

Two-day manhunt

Two apartments were raided in Chemnitz during a massive police operation on Sunday, and three other suspects were held for questioning. Two of these have since been released, though one - a 33-year-old Syrian believed to be the man who rented out the Chemnitz apartment to Jaber A. - is still being held on suspicion of helping the suspect. Both suspects currently in custody had arrived in Germany in the past two years and had submitted asylum applications.

Acting on a tip-off from Germany's domestic intelligence agency, police had raided the suspect's Chemnitz apartment on Saturday and seized 1.5 kilos (3.3 pounds) of explosive material, which was later detonated in a controlled explosion.

Police have only said that the man was originally from the Damascus area of Syria and had been granted refugee status after arriving in Germany last year.

How Jaber A. was able to evade police on Saturday was a key question of the Monday conference. He was at home when police approached his Chemnitz apartment at about 7 a.m. local time (0500 UTC).

Michaelis said that police were not sure in which apartment the suspect was hiding, and had to break off a planned raid, since there was a danger to other residents.

During this retreat, a man matching the suspect's description emerged from the building, and fled when police called on him to stop, Michaelis said. He could not confirm whether the fleeing man was Jaber A.

During the search, German police boosted security around the country, particularly around "critical infrastructure" like train stations and airports.

Political fallout

The Christian Social Union (CSU), the Bavarian wing of Merkel's center-right government coalition, said that Germany's Federal Office for Migration and Refugees (BAMF) needed to introduce a "total revision" of the registration of asylum seekers.

CSU General Secretary Andreas Scheuer said the BAMF needed to conduct individual interviews with all refugees, "because we must know who is coming to us, and who is staying with us."

In fact, a BAMF spokeswoman told DW that although individual interviews had been replaced with multiple-choice questionnaires during the height of the bureaucratic crisis caused by last year's influx of refugees, the authority currently carries out interviews with anyone applying for asylum in Germany.

Even during the crisis, she added, individual interviews were carried out in all cases where a refugee's identity could not be established.

The BAMF said on Monday that it would report all forged passports directly to the police in the future. Up until now, it had merely reported the matter to the relevant regional authority.

Editor's note: Deutsche Welle follows the German press code, which stresses the importance of protecting the privacy of suspected criminals or victims and obliges us to refrain from revealing full names in such cases.

bk,dj/bw (dpa, AFP, AP, epd)