Police in Germany have raided an apartment, finding several hundred grams of “highly volatile” explosives which it is believed was part of an airport bomb plot.

Investigators are now seeking a Syrian suspect who is still on the run and have detained a further three people for questioning who they believe could know his whereabouts.

Around 100 people were evacuated from the apartment block in Chemnitz as the bomb squad moved in to remove the explosives. The substance was then blown up in a controlled explosion.

Families living in the apartment block in Chemnitz’s Fritz Heckert district said they were woken in the early hours of the morning by police officers carrying machine guns and urging them out of the building. They were taken away from the area in buses.

A spokesperson for the police said it was a highly volatile mixture which was more dangerous than TNT.

The building was raided following a tip from Germany’s domestic intelligence agency but when police bashed down the door, the suspect had already fled.

Saxony police have now put out an alert for 22-year-old Jaber Albakr from the Damascus area and are calling for anyone who knows where he could be to get in touch.

Police have not revealed where they believe the terrorist attack was set to take place but the German news agency dpa says it has spoken to German security sources who believe the suspect is connected to Islamic extremist groups. The suspect was already known to German intelligence services although it is unclear how long he had been in the country for. According to online news reports, Albakr is suspected of plotting a bomb attack on a German airport.

It is thought he could have entered Germany last year when Germany experienced a large influx of asylum seekers from the Middle East. Nearly 900,000 asylum seekers entered Germany, most of whom were Syrians fleeing from civil war.

The explosives are thought to have contained triacetone triperoxide (TATP), which is the same substance used by suicide bombers in Paris when attackers killed 130 people in a series of coordinated shootings and a bombing across the city.

Security in Germany was already high after two terror attacks by Isis supporters earlier this year. Now police are warning people that the suspect in this latest incident should be assumed to be dangerous and everyone must remain on their guard.