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.
More about:
