At least four people were arrested in Athens on Saturday as part of a probe into a jihadist cell that was dismantled in Belgium this week, a Greek police source said, according to AFP.

Belgium later said, however, that there was no evidence that the arrests in Greece were indeed connected to the cell that was dismantled in Belgium.

Greece’s anti-terror police were seeking to determine whether those arrested included Abdelhamid Abaaoud, the 27-year-old suspected mastermind of the cell, who according to media reports may have been planning the foiled attacks from Greece.

The arrests took place in the Pangrati district of the Greek capital in the middle of the day, the source told AFP. Several mobile phones were also seized.

However, Belgian authorities told The Associated Press (AP) later Saturday that information sent to them from Athens so far has not indicated the people detained by police in Greece were involved in the Belgian cell.

After initial vetting in Brussels, federal magistrate Eric van der Sypt said the information they received showed there was no link.

A Greek official, who spoke on condition of anonymity due to the sensitivity of the ongoing probe, told AP that the “investigation is ongoing. We are in touch with the Belgians.”

European nations have arrested dozens of Islamist suspects in the wake of the Belgian anti-terror raids, during which two suspects were killed.

Belgium said the cell was planning to kill police officers.

Abaaoud, a Belgian of Moroccan descent, is a notorious jihadist who spent time in Syria. His alleged involvement comes at a time of heightened fears in Europe about the threat posed by young Europeans returning home after fighting alongside extremist groups in the Middle East.