German police on Sunday stormed another apartment in the eastern city of Chemnitz, detaining a man allegedly connected to a Syrian refugee suspected of planning a bomb attack.

"Nobody was injured, and no shots were fired. We've taken the man into custody and we are questioning him now," said Tom Berhardt, spokesman for the criminal investigation office in Saxony.

Police on Saturday raided the apartment of 22-year-old Syrian refugee Jaber al-Bakr, discovering "several hundred grams" of "explosive substance more dangerous than TNT" at his residence.

Despite several leads on the suspect's whereabouts, authorities have yet to capture the Syrian man, who allegedly escaped during the raid.

"We are following numerous tips, but unfortunately we don't have a hot lead yet," Berhardt said. "We must continue to assume that this person poses a danger."

'Islamist-oriented'

The federal prosecutor's office on Sunday took over the investigation, saying the "overall picture" suggests an "Islamist-motivated attack," according to a spokeswoman.

Although explosives had been discovered at the refugee's residence, Bernhardt said it did not necessarily mean the suspect was involved with the "Islamic State" militant group, which claimed responsibility for two attacks in Germany this year.

"This doesn't automatically mean we are talking about IS. This could also be a case of self-radicalization via the Internet," he added.

Three Syrian men arrested on Saturday are expected to appear in court later on Sunday. 

Europe has witnessed an increase in extremist attacks following an assault on the offices of satirical magazine "Charlie Hebdo" in Paris in January last year. Since then, more than 250 people have been killed in terrorist attacks across the continent, including in Nice, Brussels and Paris.

ls/rc (dpa, Reuters, AP)