has reported.
Tom Bernhardt, spokesman for the state criminal police in Saxony said officers acted on intelligence received last night and that their actions have foiled a "serious threat".
He added: "We must assume that the person is dangerous."
Mr Bernhardt said it was unclear if one or several suspects were involved and could not say whether the motivation for the planned attack was far-right or Islamist.
The luggage of two people provisionally arrested at the train station is being investigated by special forces while a third person is being interviewed after being provisionally arrested close to Chemnitz.
The station was closed while robots were used to investigate a red suitcase.
Families living in the block of flats told MDR Sachsen they were woken by police with machine guns telling them to leave the building and were removed from the area by bus.
On Saturday evening cops removed the outer cordon, allowing some residents back into their homes.
A spokesperson for Saxony Police said: "We are carrying out a large operation in Chemnitz following suspicion of preparations for a bomb attack.
"Major road closers and evacuations are necessary.
"Please stay within the cordoned-off areas in your homes and follow the instructions of police."
A police officer in protective clothing watches on as a remotely controlled bomb disposal robot lifts a suitcase on a platform Chemnitz Central Station Credit: EPA Armed police raided an apartment this morning and found highly sensitive explosives Credit: AP:Associated Press Armed police continue to search the area for a suspect
The city's train station was temporarily closed as police hunt for a suspect after foiling a bomb plot Credit: DPA A special unit police unit in the east German city of Chemnitz Credit: DPA There is a huge police presence in Chemnitz as police hunt a suspect believed to have been planning a bomb attack Credit: Ruptly Police have asked local residents not to share pictures of their operation on social media.
Police had earlier tweeted: "At the moment we have a static threat situation in the Fritz-Heckert area in Chemnitz, C0810 and with strong forces on the ground."
Chemnitz is in the east German district of Fritz Heckert.
Germany had until the summer been spared the kind of militant attacks suffered by neighbouring France and Belgium.
But in late July, Islamic State claimed two attacks - on a train near Wuerzburg and at a music festival in Ansbach - in which asylum-seekers wounded 20 people in total.
German Chancellor Angela Merkel's open immigration police has come under fire following the attacks.
German police said previously they had identified 523 people who posed a security threat to the country, around half of whom were known to be currently in Germany.
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