Spanish police have arrested a Russian programmer for alleged involvement in "hacking" the US election, Spanish press reports have said.
Pyotr Levashov, arrested on 7 April in Barcelona, has now been remanded in custody.
A "legal source" also told the AFP news agency that Mr Levashov was the subject of an extradition request by the US.
The request is due to be examined by Spain's national criminal court, the agency added.
El Confidencial, a Spanish news website, has said that Mr Levashov's arrest warrant was issued by US authorities over suspected "hacking" that helped Donald Trump's campaign.
Mr Levashov's wife Maria also told Russian broadcaster RT that the arrest was made in connection with such allegations.
Several cybersecurity experts, including Brian Krebs, have also linked Mr Levashov to a Russian spam kingpin, who uses the alias Peter Severa.
A US intelligence report released in January alleged that Russian President Vladimir Putin tried to help Mr Trump to victory.
Mr Trump later commented that the outcome of the election had not been affected.
The report said that Russia's objectives were to "undermine public faith" in the US democratic process and "denigrate" Mr Trump's Democrat rival Hillary Clinton.
Russia's efforts to this end allegedly included hacking into email accounts used by the Democratic National Committee; using intermediaries such as WikiLeaks to release hacked information; and funding social media users or "trolls" to make nasty comments.
However, there were no details of Mr Putin's alleged involvement with such interference in the report.
Mr Putin has strongly denied allegations that Russia tried to influence the US election.