French police say they have arrested a 22-year-old Afghan linked to a countryman in the United States suspected of planning an election day attack there.
On Saturday, French anti-terrorism prosecutors said the man, who was arrested Tuesday in southwestern France, is suspected of being an Islamic State supporter.
He was reportedly linked to a 27-year-old Afghan arrested Wednesday in Oklahoma and charged with plotting a November election-day attack on a football stadium or a shopping centre.
One source close to the case said the two men were brothers, but prosecutors have not yet confirmed this.
The US-based suspect had been in contact via the Telegram app with a person identified by the FBI as an Islamic State recruiter, US officials have said.
They reportedly alerted their French colleagues, leading to the arrest of three people aged 20 to 31 in southwestern France.
While the main suspect remains in detention, according to prosecutors, the other two have been released.