MILAN (AP) -- Venice's mayor resigned under pressure Friday, a day after being freed from house arrest under a plea deal linked to a bribery scandal involving the construction of underwater barriers to protect the lagoon city from flooding.

The scandal centered on the 5 billion-euro ($6.8 billion) Moses project is just one of several kickback probes in recent weeks that have piled pressure on Prime Minister Matteo Renzi to tackle Italy's endemic corruption, which has deterred international investment and eroded public trust.

Venice's mayor Giorgio Orsoni, above, has resigned amid a corruption scandal a day after being released from house arrest under a plea deal. (AP Photo/Luigi Costantini, File)

His government is expected to enhance the powers of the newly appointed anti-corruption czar later Friday, followed by a new anti-corruption law in a few weeks.

Venice mayor Giorgio Orsoni was among more than 30 people arrested last week in a wide-ranging probe that alleged the consortium building the barriers had amassed a 25 million-euro ($34 million) slush fund abroad to bribe officials.

The ambitious barrier project, meanwhile, has suffered long delays and is more than four times over its initial cost projection. It is currently expected to be finished by 2016.

Orsoni has said he was unaware that any donations to his 2010 election campaign were illegal. He was released from house arrest Thursday after accepting a four-month suspended sentence.

Orsoni, who ran for the Democratic Party without officially joining its ranks, indicated Friday he had lost support of the party. Several city council members had called for his resignation overnight, and he derided those comments as "opportunistic and hypocritical reactions."

Also Friday, a longtime ally of former Prime Minister Silvio Berlusconi who authorities said fled to Lebanon to escape a prison sentence for Mafia association was extradited to Italy under Interpol guard. Marcello Dell'Utri was transferred to a prison in the northern city of Parma.