Bulgaria has extended the deadline for bids for the contract for to run Sofia airport until May 19 as the country prepares for early elections in the spring, the transport ministry said on its website on Monday.

The transport ministry launched the tender to operate the Balkan country’s main airport for 35 years in May last year, expecting to bring some 1.2 billion levs ($658.69 million) into state coffers.

It has since extended the deadline four times. In November, the centre-right government, which resigned after losing the presidential election, delayed the tender to the end of January following calls from the opposition Socialists to scrap it.

The fresh delay will allow a new government expected to take over after early general elections seen likely at the end of March to decide on the tender.

Turkey’s Limak Holding, Russia’s VTB Capital and Switzerland’s Flughafen Zuerich were planning to jointly bid for the right to operate the airport, a source familiar with the process had told Reuters.

German airport operator Fraport has said it was considering whether to participate and local media has reported that Turkish airports group TAV, in which French Groupe ADP has a 38 percent stake, was also considering a bid.

The airport, which was used by 5 million passengers last year, is currently operated by the state.