Victor Ponta. | EPA Embattled Romanian leader claims bum knee, steps aside After years of pressure to crack down on corruption, Romanian prosecutors are starting to target some big fish.

Romanian Prime Minister Victor Ponta is under investigation for forgery, money laundering, tax evasion and conflict of interest — but it took a basketball injury to get him to temporarily step aside.

Ponta was due at the prosecutor’s offices Monday to hear further details of the charges, but instead issued a statement on Facebook, from Turkey, saying he had undergone knee surgery there for an injury picked up playing basketball and would be taking time off to recover.

Ponta wrote to President Klaus Iohannis asking to temporarily step down as prime minister and requesting that Ponta’s deputy, Gabriel Oprea, be named as stand-in. Iohannis agreed, although only after Ponta sent medical documents proving his inability to work. The constitution allows Oprea to serve for up to 45 days.

But Ponta's problems go much deeper than a possibly bum knee. Earlier this month, Romania’s National Anti-Corruption Directorate alleged that while working as a lawyer in 2007, Ponta was paid roughly €40,000 for work he didn’t do by another lawyer who later became a cabinet minister in his government.

The chief prosecutor, Laura Codruta Kovesi, who has recently run a string of successful prosecutions targeting Romania’s elite, also alleged that Ponta and the lawyer, Dan Sova, forged documents to justify the work once Ponta was a government minister in 2011.

Ponta denied the charges, and rejected calls from Iohannis — who beat Ponta in the presidential election last November — to resign.

“I was appointed by parliament and only parliament can dismiss me!” he wrote on his Facebook page.

The parliament, where Ponta’s Social Democratic Party and smaller allied parties hold a majority, voted against a no-confidence motion on the prime minister earlier this month and against lifting his immunity to face conflict-of-interest charges.

The case highlights the increasingly successful battle against corruption in one of the EU’s newest member states. In January, a European Commission progress report on judicial reform and anti-corruption praised the anti-graft prosecutions of serving and former ministers, parliamentarians, mayors, judges and senior prosecutors.

However, it noted that the parliament’s responses on lifting parliamentary immunity for targeted MPs were “arbitrary and lacking objective criteria.”

“It is a problem with the system,” said Paul Ivan, a Romania expert at the European Policy Centre in Brussels. “The parliament is not allowing in all cases the justice system to operate effectively.”

But Ivan said high-profile cases such as Ponta's were evidence of progress. “The fact that the prime minister is put under investigation is a sign that this part of the justice system is functioning.”