Two men have been arrested in Birmingham and Manchester as part of the investigation into the Texas synagogue attack by British hostage-taker Malik Faisal Akram.
Akram, 44, originally from Blackburn in Lancashire, took four people hostage at the Congregation Beth Israel synagogue in Colleyville on Saturday.
He was shot dead when FBI entered the building following a 10-hour stand-off.
Announcing the latest development, Greater Manchester Police said: “Officers from Counter-Terror Policing (CTP) North West continue to support US authorities with their investigation into the events in Texas.
“As a result of this ongoing investigation, two men have been arrested this morning in Birmingham and Manchester.
“They remain in custody for questioning.
“CTP North West officers continue to liaise with and support colleagues from other forces.
“Communities defeat terrorism and the help and support we get from the public is a vital part of that.
“So, we would urge everyone to remain vigilant, and if you do see anything suspicious then please report it, in confidence, to police via the anti-terrorist hotline or gov.uk/ACT
“It won’t ruin lives but it may well save them.”
Two teenagers arrested in Manchester following the incident were released without charge on Tuesday.
Akram was previously investigated by M15 in 2020 but was not deemed to be a credible threat to national security at the time.
It is not yet clear how Akram, who had a criminal record in the UK, was able to travel to the US two weeks ago. US officials believe Akram had a visa, arrived at John F Kennedy International Airport in New York and bought the handgun used in the incident.
According to reports, he stayed at a homeless shelter and is believed to have bought a gun on the street.
During the stand-off with police, Akram demanded the release of Pakistani neuroscientist Aafia Siddiqui, who was convicted of trying to kill US army officers in Afghanistan, and is in prison in Texas.
US President Joe Biden has branded the incident “an act of terror”.
The FBI in Dallas had earlier said there was nothing to suggest a wider terror plot.
Akram’s family said they were “absolutely devastated” by what had happened and “do not condone any of his actions”, according to a statement that was shared on the Blackburn Muslim Community Facebook page.
The statement was attributed to Akram’s brother, Gulbar. He said he had been involved in negotiating from the UK with his sibling during the ordeal, and added that the hostage-taker “was suffering from mental health issues”.