Three Syrian men have been arrested on suspicion of planning an attack in Düsseldorf for Islamic State while a fourth suspect who told officials in Paris about the alleged plot is in custody in France, prosecutors in Germany have said.

The federal prosecutor’s office said the three men were arrested in three different German states on Thursday.

It said in a statement that the plan was for two men to blow themselves up in central Düsseldorf before further attackers killed as many people as possible with firearms and explosives.

However, it said there were no indications that they had started concrete preparations, and the plan was thwarted when one of the plotters alerted French prosecutors in February.

The three men arrested in Germany were identified as Hamza C, 27; Mahood B, 25; and Abd Arahman AK, 31. The suspect in custody in France was identified as Saleh A, 25, also from Syria. Their full names were not released under German privacy rules.

Prosecutors said that Saleh A and Hamza C joined Isis in Syria in 2014 and got instructions from the group’s leadership to carry out an attack in Düsseldorf.

The two travelled to Turkey in May 2014 with Isis’ approval, they added. In March and July 2015, they travelled separately via Greece to Germany.

The pair convinced Mahood B to join the plot at some point before January this year, prosecutors said.

Also in January, Saleh A contacted Abd Arahman AK, who had travelled to Germany in October 2014 with instructions from Isis to take part in the attack. According to prosecutors, Abd Arahman AK, who had made suicide vests and grenades for the extremist al-Nusra Front in Syria, was supposed to make the suicide vests for the planned attack.

The plot was thwarted when Saleh A told prosecutors in Paris on 1 February about the plan. He has since remained in custody in France and German prosecutors are seeking his extradition.

Prosecutors stressed that the arrests are not related to the Euro 2016, which kicks off in France next week.