Two more suspects were arrested in connection to the arson attack on a Czech optics and drone factory in March, allegedly carried out by a pro-Palestinian group that claimed responsibility for the incident east of Prague.

Czech police and a public prosecutor’s office previously announced five detentions, including of an American and an Egyptian, Reuters reported on Saturday.

Two Polish nationals were also detained in connection to the case.

The latest suspects were detained separately on Saturday and Friday, with the latter taking place in Bulgaria.

Extradition for the suspect will be requested, police were cited as saying.

The group that claimed responsibility for the ⁠firebombing is named “The Earthquake Faction” and identifies as “an internationalist underground network that targets key sites critical to the Zionist entity,” aiming to “destroy all limbs of empire from within, by any means effective.”

In a statement online after the incident, it claimed that it struck the “epicenter of the Israeli weapons industry in Europe. … The Earthquake Faction intervened to … set the factory ablaze. No one was harmed.”

LPP Holding, the targeted security firm, announced plans ⁠to cooperate with Israeli company Elbit Systems in 2023, but now says that those plans were never executed, according to Reuters.

The arson took place on March 20 at an industrial complex in Pardubice, a city about 75 miles east of Prague.

A spokesman for the Pardubice District Court said after an appearance at court by the first pair of suspects that they face 20 years in prison, according to Czech outlet Novinky.

“It’s a terrorist crime. Neither of the accused pleaded guilty, they practically did not testify,” he added.