The leader of Portugal's center-right Democratic Alliance (AD), Luis Montenegro, claimed victory in Sunday's closely contested parliamentary election.

"It seems inescapable that the AD won the elections and that the Socialists lost," he said in an address in Lisbon shortly after midnight.

Montenegro said he expected President Marcelo Rebelo de Sousa to formally invite AD to form a government.

However, the official results, which were nearly complete early Monday, showed that the DA was still short of a majority. This complicates the political scenario as Montenegro also reiterated his election promise not to rely on far-right support to govern or strike any deals with right-wing populists.

Exit polls showed the far-right party Chega (Enough) making sizeable gains, while its leader said the party was "available to build a government."

The center-left Socialist Party (PS), which has been in power since 2015, conceded defeat, with leader Pedro Nuno Santos congratulating the DA on their win.

Tight race to the finish

The near-complete official results showed that the Democratic Alliance garnered 29.49% of the votes in Sunday's election, narrowly beating the Socialists, who received 28.66%.

This would mean the AD is poised to secure 79 seats in the 230-seat legislature, compared to 77 seats for the Socialists.

The PS has faced public ire recently as a corruption investigation forced Socialist Prime Minister Antonio Costa to resign.

The far-right Chega (Enough) party's 18 percent of the votes means that the party could have 48 seats, a significant increase from the 12 seats it won in the previous election in 2022.

With no party claiming a clear majority, it now comes down to AD to form a governing coalition. 

Around 10.8 million people were eligible to vote to elect 230 legislators to the Portuguese parliament.

The campaign focused on corruption, economic concerns, and health care.

Chega leader says 'available to build a government'

Chega party leader Andre Ventura told reporters that the results were looking "absolutely historical" for his party after the polls closed. 

"It's the end of the two-party system," the lawyer and former football commentator said. 

"We want to give Portugal a stable government," Ventura said after the exit poll was released. "We are available to build a government in Portugal." 

Although some members of the center-right AD alliance have been more evasive on the question, party leader Luis Montenegro had said several times before the vote that he would not ally with Chega. 

However, his options may prove limited if he aims to form a coalition with a majority that does not include AD's main rivals PS, who also rule out working with Chega. 

The AD would face a tough challenge to form a government without Chega amid its surging popularity.

Conservative President Marcelo Rebelo de Sousa faced criticism on Friday after he said in an interview that he would do everything he could to prevent Chega from gaining power. He was called out for deviating from his mandate of remaining neutral.

Chega's election manifesto vowed to address "excessive" immigration and government corruption. Since the 2022 election, the far-right party has seen its support base more than double.

That would mirror gains by far-right parties across Europe.

Why were the elections held early?

The early election was called two years ahead of schedule after former Socialist Prime Minister Costa resigned due to corruption investigations involving his chief of staff.

Costa himself has not been accused of any crime.  

The investigations involved alleged illegalities in how his government handled major investment projects.

msh, ss/jsi (Reuters, dpa, AP, AFP)