Prosecutors have questioned Romania's prime minister on suspicion of wide-ranging corruption charges connected to work he did as a lawyer eight years ago.

Premier Victor Ponta, who is recovering from a knee operation, arrived at the prosecutors' office Monday, and walked up the steps on crutches into the building where he was questioned.

He resigned as chairman of the ruling Social Democratic Party on Sunday, saying he wanted to prove his innocence.

On June 5, prosecutors said the 42-year-old Ponta was suspected of tax evasion, money laundering and making false statements for work he did when he was a lawmaker.

Ponta went to Istanbul for his knee operation on June 15 and stayed for more than three weeks. He resumed his duties as prime minister on July 9.