Croatia has formally asked Austria to extradite former Prime Minister Ivo Sanader to face a corruption inquiry.
Mr Sanader, who is now an independent MP, left Croatia last Thursday as parliament moved to strip him of his immunity from prosecution.
He was arrested the following day on an Austrian motorway after Croatian police issued a warrant.
Mr Sanader denies all the accusations against him, saying they are politically motivated.
Croatia's justice ministry sent a request for his extradition to its counterpart in Vienna, Croatian state media report.
He is the highest-ranking Croatian official to be investigated for corruption, Reuters news agency reports.
The warrant says he is suspected of conspiring to commit crime and abuse of office.
Croatia is conducting a wide-ranging investigation into alleged corruption, designed in part to prove its readiness to join the EU.
Mr Sanader, who became prime minister in 2003, resigned unexpectedly in July 2009 in the middle of his second term as leader.
Last January he was expelled by the governing Croatian Democratic Union but he carried on as an independent MP.