MOSCOW (AP) — Russia's Justice Ministry on Friday added Mikhail Kasyanov, who was President Vladimir Putin's first prime minister but then became one of his opponents, to its register of “foreign agents.”

Russian law allows for figures and organizations receiving money or support from outside the country to be designated as foreign agents, a term whose pejorative connotations could undermine the designee's credibility.

The law, which has been extensively used against opposition figures and independent news media, also requires material published by a designee to carry a prominent disclaimer stating that it comes from a foreign agent.

The ministry's website says Kasyanov “took part in the creation and dissemination of messages and materials of foreign agents to an unlimited circle of people, disseminated false information about the decisions taken by public authorities of the Russian Federation and the policies pursued by them” and “opposed the special military operation in Ukraine.”

Kasyanov became prime minister in 2000 after Putin was elected to the presidency and served through 2004, when he was dismissed. He was primarily responsible for economic reforms, including Russia's adoption of a flat income tax.

He became a prominent opposition figure after leaving office and attempted to run for president in 2008, but his candidacy was rejected by the national election commission.

Kasyanov later faded from view as Russia's opposition weakened under arrests and repressions. After Putin sent troops into Ukraine in February 2022, Kasyanov left the country and has been reported to be in Latvia.