German website Spiegel Online said Jaber Albakr had killed himself despite being under round-the-clock surveillance due to being at risk of suicide or hunger strike.

It is not yet clear how he killed himself, Spiegel reported, citing judicial sources.

The 22-year-old had been arrested in Leipzig on Monday morning after two days on the run.

Police had found "several hundred grams" of a volatile explosive at his flat - enough to cause significant damage - but he managed to flee from the property in Chemnitz on Saturday.

He was handed over to police by three other Syrians who recognised him from photos released as part of a nationwide manhunt.

The weekend raid came after Saxony police were tipped off by Germany's domestic intelligence service, who had been monitoring Albakr since last month.

Prosecutors said there was no evidence he had chosen a target for an attack, but he had been searching online for bomb-making instructions and "equipment for jihad" since at least the beginning of the month.

German authorities said Albakr was originally from Damascus and was among 890,000 migrants granted asylum after entering the country in 2015.