ZAGREB — Croatia began a retrial on Monday of former Prime Minister Ivo Sanader on corruption charges, including a case of a bribe allegedly taken from Hungarian oil firm MOL to allow it acquire a dominant stake in Croatia's biggest utility. In July, Croatia's Constitutional Court annulled two corruption convictions against Sanader, for which he received eight-and-a-half years in prison, citing procedural errors, and ordered the retrial. Sanader, prime minister from 2004 to 2009, was convicted of taking the bribe from MOL in 2008 so it could take the stake in Croatian oil firm INA. Sanader and MOL have denied any wrongdoing. He was also convicted of taking a bribe from Austria's Hypo Bank in 1994 and 1995, when he was deputy foreign minister. He is the highest-ranking Croatian official tried for graft as part of the ex-Yugoslav republic's drive to strengthen the rule of law and join the European Union, which it did in 2013. As the retrial got under way, Sanader's lawyers requested the judge be changed as he had overseen the previous trial. After the Hungarian firm's acquisition of the stake in INA, Croatia has been trying for years to claw back influence in decision-making the firm where MOL holds just under 50 percent. Zagreb and MOL have been engaged in talks on improving their partnership in INA since September 2013 but have made little progress and further talks are unlikely before Croatia's parliamentary election, due by early 2016. The Zagreb county court has indicted MOL Chairman Zsolt Hernadi after Hungary refused to allow him to be questioned, citing national interests. Hernadi has denied any wrongoing. A trial due to start in February has been postponed for procedural reasons, with no new date set. Meanwhile, Sanader also faces other corruption charges in separate cases, including an indictment for creating slush funds for the conservative HDZ party by taking money from public companies. — Reuters