Front-running presidential candidate Rodrigo Duterte talks to journalists Monday after voting in the Philippines. (Bullit Marquez/AP)

Rodrigo Duterte, a brash and unflinchingly authoritarian mayor, looks poised to be the next president of the Philippines, building a seemingly insurmountable lead in Monday’s presidential election, according to unofficial partial results, and drawing a concession from a top rival.

Duterte, who goes by nicknames such as “the Punisher” and “Duterte Harry” — a local twist on the movie lawman “Dirty Harry” — was far ahead of four main rivals, winning nearly 40 percent of the vote, early returns showed. He was the heavy favorite heading into the election despite promising to kill suspected criminals and joking about rape. Final official results may take days.

But with most votes counted, one of Duterte’s top challengers, Sen. Grace Poe, called him late Monday to concede, Philippine news media reported. Although she had denounced him as an “executioner” during the campaign, Poe told reporters that voters have given him “a mandate,” adding, “Let’s give him a chance.”

Duterte’s backers see him as a crime-busting savior.

“I think he’ll bring about the change we all long for,” said Mhanwell Duran, 19, as he waited to cast his vote.

Filipino presidential candidate and longtime Davao City mayor Rodrigo Duterte has stirred up contention with his brash, off-color statements on rape, extrajudicial killings and more. (Jenny Starrs/The Washington Post)

Critics, though, worry about a return to the strongman politics of the past in a country that is one of Washington’s closest allies in the region.

More than 140,000 police officers and soldiers were deployed across the island nation to protect its voting centers, numbering about 36,000. The Philippines has a long tradition of election violence, fueled by lax law enforcement and politicians with private armies.

Just before the polls opened, seven people were killed and one was wounded when armed men attacked a vehicle outside the capital, Manila. Chief Superintendent Wilben Mayor, a spokesman for the Philippine National Police, said the victims — all supporters of a local mayor — were shot in the head.

The race featuring Duterte and four challengers was fought primarily on domestic issues, including crime, corruption and transportation. With China pressing its claims in the South China Sea and the United States boosting its military role in the Philippines, foreign relations also loomed large.

But the contest came to be defined by Duterte’s rhetorical fireworks. The 71-year-old has made headlines for, among other comments, calling Pope Francis “a son of a whore” in a predominantly Roman Catholic nation and saying that he wished he had “been first” to rape an Australian woman killed in a 1989 prison riot.

There was even a promised stunt — vowing to ride a Jet Ski to a disputed shoal in the South China Sea.

The longtime mayor’s provocative comments have earned him comparisons to Donald Trump and tag lines such as “Trump of the East.”

Duterte dislikes the notion — “Trump is a bigot; I am not,” he said — but he does not bristle at another word used to describe him: dictator. He said he would dissolve the country’s congress and install a “revolutionary government” if he needs to.

“I am a dictator? Yes, it is true,” he said.

For many in the Philippines, where the 1986 People Power Revolution ended three decades of dictatorial rule, the comment crossed a line. “Years of trying to put up a democratic state and we waste it for what?” asked Alisson Atis, a 26-year-old student. “For one ruling body?”

But millions of others seem to gravitate to Duterte’s combative ways, seeing him as a political outsider who can shake up the status quo.

In the Philippines, democracy is a family business. President Benigno Aquino III is the son of a former president. Presidential hopeful Manuel Roxas II’s grandfather once ruled the country. Among the candidates for vice president: Sen. Ferdinand R. “Bongbong” Marcos Jr., son of disgraced former ruler Ferdinand E. Marcos and his wife, Imelda Marcos.

Although the country has had solid economic growth under Aquino, poverty and inequality persist. Many voters think that Aquino failed to deliver real change and are drawn to Duterte’s big promises.

“This is a fight against the administration,” said Edmund Tayao, a professor of political science at the University of Santo Tomas in Manila. “It’s a protest vote because it’s an anti-establishment vote.”

Unlike Aquino and others, Duterte made his name in the country’s less-developed south. He spent more than 20 years as the mayor of Davao, where he patrolled the streets on a Harley-Davidson motorcycle and gave interviews with a pistol tucked in his waistband.

As mayor, he made tackling crime his signature issue, but his law-and-order campaigns included the summary execution of criminals. A 2015 Human Rights Watch report traced the rise of Davao’s “death squad mayor.”

Rather than distance himself from the title during the campaign, Duterte seemed to welcome it, musing about his plans to “kill all” criminals and feed their bodies to fish. He has promised to eliminate crime and corruption in six months if he becomes president.

On foreign policy, Duterte is seen as something of a wild card. The next president faces the unenviable task of trying to balance China as it presses its maritime claims off the Philippine coast and to safeguard the country’s alliance with the United States, which seeks to increase its military presence in the area in response.

In addition to his Jet Ski plan, Duterte has said that he would consider putting aside differences with China if Beijing offered some big-ticket railway projects on his home island of Mindanao.

Assuming he holds his lead in the final tally, the question is how Duterte plans to deliver on his tough talk. “His cabinet members will have many things to do in terms of giving him advice more or less consistent to the national interest, because he is not really into national policy,” Ramon Casiple, executive director of the Institute for Political and Electoral Reform, said in Manila.

“But the problem is,” Casiple added, “he is not listening to his advisers . . . when they are telling him to shut his mouth.”

Rauhala reported from Beijing.