According to unofficial reports, Sanader is suspected of receiving a EUR 10 million bribe from the Board chairman of the Hungarian oil company MOL, Zsolt Hernadi, in exchange for management rights in the Croatian oil company INA.

Apart from Sanader and Hernadi, USKOK's investigation order includes former Deputy PM Damir Polancec, who is not suspected of taking bribes but helping Sanader abuse office.

Without revealing details of the new investigation, USKOK said on its website that it submitted to Austrian judicial bodies on June 10, via the Croatian Justice Ministry, a plea for Sanader's extradition in connection with the new investigation order.

USKOK said in a statement the suspicion was based on information collected with help from Austria, Switzerland and Eurojust.

The head of the Austrian Justice Ministry department on international criminal law, Barbara Goeth-Flemmich, told press the ministry received USKOK's request for expanding the investigation into Sanader about 10 days ago, but added she could not talk about the content of the request.

She said Sanader might be extradited in three weeks' time, explaining that after he withdrew his appeal against a decision on his extradition, an appellate hearing was cancelled and Sanader now had to reiterate before a judge in Salzburg that he agreed to being transferred. This is expected to take place today.

His official statement is then sent to the Austrian Justice Ministry, which notifies the judicial bodies in Croatia, after which the ministry notifies the court in Salzburg that the court will coordinate Sanader's transfer to Croatia, which Goeth-Flemmich said should take three weeks.

She said that after Sanader agreed to the extradition, Croatian judicial bodies could launch investigations and court proceedings in any case against him, not only in those for which the Salzburg court approved extradition.

According to the print media, USKOK suspects that in 2008 and 2009, Sanader and Hernadi agreed to change, for a EUR 10 million bribe, the agreement between the Croatian government and MOL about INA, so that MOL could take over management rights in the Croatian company.

They are also suspected of agreeing to separate INA's gas business by leaving MOL its profitable part, while the government would manage the non-profitable part.

The negotiations on the agreement changes were led by Polancec on the government's behalf.

Polancec told the media he received the investigation order through his lawyer a few days ago but that he could not make any comment, as USKOK's investigations were confidential.

According to the media, Sanader knew the agreement changes were harmful for Croatia, but he and Polancec misled the government and the presidency of the ruling HDZ party into thinking that the agreement was extremely favourable, so it was signed and Sanader took the MOL executive's bribe. Half the money, EUR 5 million, was allegedly paid via a company co-owned by his friend Robert Jezic, the owner of the DIOKI company whom USKOK is investigating in another case.

The media speculate that the State Prosecutor's Office is preparing a request for Hernadi's arrest and extradition.