Exiled opposition politician Mikheil Saakashvili called on European nations Tuesday to impose sanctions on Ukrainian President Petro Poroshenko and his inner circle, accusing them of violating his human rights.

Saakashvili said that Poroshenko, his former ally, breached international law by stripping him of his Ukrainian citizenship and forcibly kicking him out of the country.

Speaking in The Hague, Netherlands, Saakashvili and a legal expert said sanctions should be used to push Poroshenko into restoring the opposition leader’s citizenship and to target assets that Saakashvili alleged Ukraine’s leaders obtained illegally.

“We are looking for their assets across Europe to impound them, because they were stolen from the Ukrainian people,” he said.

International law expert Geoffrey Robertson said international diplomacy is the best way forward for Saakashvili, who cannot take his case to European courts until he has exhausted his options in Ukraine’s slow-moving judicial system.

“There is no immediate solution that European law offers,” said Robertson, who accompanied Saakashvili to The Hague. “It is time for diplomatic action to be taken to ensure that Ukraine changes its position.”

Saakashvili was Georgia’s president from 2004 to 2013, and later was given a governorship in Ukraine by then-ally Poroshenko. However, he has since led anti-government protests and criticized the president for failing to stem corruption.

Saakashvili was detained in February in Kiev by armed, masked men and deported to Poland. His expulsion means he is unlikely to be able to take part in next year’s presidential election in Ukraine.

“I don’t have personal ambitions,” he said when asked about the election. “But I have [the] ambition to help Ukrainian democracy, to help Ukraine in the corruption fight.”