Istanbul has been forced to turn to foreign banks to find money for frozen infrastructure projects because Turkey’s state lenders have refused financing for the municipality since President Recep Tayyip Erdogan’s party lost control of the country’s biggest city, its new mayor said.

The city of 16 million people needs more 20 billion lira ($3.48 billion) to finish metro rail projects and other investments, but publicly owned banks have ceased extending even short-term credit to Istanbul and other municipalities controlled by the opposition Republican People’s Party, Mayor Ekrem Imamoglu told a news conference on Sunday.

Imamoglu has emerged as a rival to the powerful Erdogan since beating the ruling party’s candidate for mayor not once but twice after the president forced a re-run election in June. Erdogan himself launched his political career as Istanbul's mayor and his political movement controlled the city for a quarter century before Imamoglu’s upset victory.

Control of Istanbul was a major source of patronage for the ruling Justice and Development Party (AKP), which was able to hand out lucrative contracts and jobs under the city’s $4 billion budget. Imamoglu campaigned on a pledge to do away with wasteful spending, and on Sunday he blamed the previous administration’s mismanagement over the past half-decade for tripling city hall’s debt to 28 billion lira ($4.87 billion).