Mr Lieberman was a controversial choice for foreign minister
Israel's new Foreign Minister, Avigdor Lieberman, has been questioned by police for at least seven hours over corruption allegations.
Police said Mr Lieberman was questioned under caution on suspicion of "bribery, money-laundering and breach of trust" as part of an ongoing investigation.
Mr Lieberman was sworn in as foreign minister on Tuesday.
He has previously denied any wrong-doing and says the corruption probe against him is politically motivated.
Police confirmed that the interview had been scheduled in advance with Mr Lieberman.
Micky Rosenfeld, a police spokesman, said Mr Lieberman had been questioned over the long-standing investigation into his business dealings, the Associated Press reported.
The accusations are believed to relate to a company run by Mr Lieberman's daughter.
A spokesman for Mr Lieberman said it was "the same investigation that has been ongoing for the past 13 years and which he has petitioned the courts to have speeded up.
"He co-operated fully with police investigators and answered all their questions and enjoyed drinking their coffee," said the unnamed spokesman.
Mr Lieberman, an ultra-nationalist, is one of Israel's most outspoken politicians.
He was a controversial choice for a leading ministerial post in the government of right-winger Benjamin Netanyahu, which was sworn in on Tuesday.
As he assumed office, Mr Lieberman raised concerns among some people by saying Israel was not bound by a US-sponsored 2007 agreement to reach a peace deal with the Palestinians.
Palestinian officials described him as an "obstacle to peace" whose policies would rebound negatively on Israel.
Israel's former chief peace negotiator, and Mr Lieberman's predecessor as foreign minister, Tzipi Livni, said the remarks showed that the government would not be a partner for peace with the Palestinians.
The BBC's Jo Floto in Jerusalem says Mr Lieberman's supporters are unlikely to be troubled by the police interest in him.
But Wednesday's questioning will do nothing to reassure those people who believe Mr Lieberman is an unsuitable choice for such a prominent role in the Israeli administration, says our correspondent.