Czech and Slovak police have detained three people, including US and Czech citizens, on terrorism charges ​following an arson attack on an arms producer’s facility claimed by a group that says ‌the company develops weapons in cooperation with an Israeli firm.

Two of the suspects from Friday’s attack were detained in the Czech Republic and one in Slovakia, Czech police said on X on Tuesday.

“We continue to work intensively to apprehend ​the remaining suspects, also in cooperation with foreign partners,” the police said.

The fire damaged ​a building used by the Czech defence group LPP Holding at an industrial complex ⁠in Pardubice, about 120 km east of the capital Prague.

LPP Holding announced plans to cooperate ​with Israeli group Elbit Systems in 2023, but says those plans have not been carried out.

LPP ​production includes drones that are exported to Ukraine, which has been fighting Russian forces since Moscow’s 2022 full-scale war.

Police had charged those detained with terrorism offences, Prague High Prosecutor Zdenek Stepanek said in a statement.

Prosecutors asked a court ​to remand the two detained in the Czech Republic into custody.

Police declined to specify whether the ​detainees were two Czechs and one US citizen or vice versa.

Czech news website Denikn.cz quoted Stepanek, the prosecutor, as saying that the most probable motive was the claim by the group that said it carried out the attack that LPP cooperated with the Israeli firm.

LPP had earlier said police ​were also looking at ​a possible Russian link ⁠in the arson attack.

Police have not publicly commented on a possible Russia link but said they were looking at different scenarios in their ​investigation.

Russia has denied previous accusations that it has carried out hybrid attacks ​in European Union ⁠countries.

The group that said it was behind Friday’s fire posted a statement on its website on Tuesday, saying it had taken “restricted documents” which it would publish if LPP did not cut ties to Elbit ⁠Systems and “denounce ​the barbaric occupation of Palestine”.