A 22-year-old Syrian Isis suspect arrested in Leipzig on Sunday after a police manhunt planned a bomb attack on Berlin airport, according to Germany's domestic intelligence chief.

In an interview with German broadcaster ZDF on Tuesday, Germany's domestic intelligence chief Hans-Georg Maassen, said that intelligence initially suggested the suspect, named as Jaber al-Bakr, planned to attack trains in Germany.

"Later, the plans became more specific and directed at airports in Berlin," said Maassen.

Police had placed al-Bakr under surveillance, and decided to arrest him when he was spotted buying glue at a cheap shop. "We have assumed that this might be the last chemical ingredient he needed to make a bomb," Maassen said.

In a raid on al-Bakr's flat on Saturday, Chemnitz police found 1.5 kg of explosives primed for use, however the suspect evaded capture. Police launched a two-day manhunt which ended when a group of refugees in Leipzig contacted police to say they were holding al-Bakr after he visited their flat.

Al-Bakr sought refuge in Germany two years ago, and police said after his arrest he was believed to have been in touch with Isis.

In police raids on two flats in Chemnitz on Sunday, three suspects were held for questioning. Two have been released, though a 33-year-old Syrian who rented the flat to al-Bakr has been held for further questioning.

In July an Afghan teenager injured several people in an axe attack on a train near Wuezberg, and a Syrian refugee committed a suicide bomb attack near a music festival in Ansbach. Both attackers pledged allegiance to Isis in propaganda videos released after their deaths.

The attacks have seen declining public support for Chancellor Angela Merkel and her open door refugee policy.