“There will never be a time that I will go to America during my term, or even thereafter. So what makes that guy think I'll go to America? I've seen America, and it's lousy,” Duterte told reporters Friday about McGovern.

McGovern led a hearing in Congress Thursday on Duterte's drug war that has resulted in a mass killing of suspected addicts and dealers in the Philippines. More than 7,000 deaths have been reported from July 1, 2016, to Jan. 21, according to the Philippine National Police. The deaths were carried out by both police and unknown vigilantes.

Human rights groups have strongly criticized the Filipino leader's method in eradicating his country's drug problem, citing lack of due process and killings that targeted the poor.

“We should be clear what an extrajudicial killing or execution is: It is the purposeful killing of a person by governmental authorities without the sanction of any judicial proceeding,” McGovern said in his opening remarks. “No arrest. No warrant. No judge. No jury. Simply, murder.”

McGovern added that someone with Duterte's abysmal human rights record should not be invited to the United States. “If he comes, I will lead the protest,” the congressman said. “We ought to be on the side of advocating for human rights, not explaining them away.”

Duterte shot back Friday, telling reporters that he, too, can — and will — investigate the United States' history of human rights violation.

“You're investigating me and the internal affairs of my country? I'm investigating you, and I will investigate you, and I will expose it to the world what you did to the Filipino, especially to the Moro Filipino,” Duterte said, likely referring to the Battle of Bud Dajo in 1906 in the island of Jolo in the southernmost part of the Philippines. American troops killed hundreds of Moro people as they tried to take control of Mindanao, home to the country's Muslims.

Duterte has frequently brought up the massacre when confronted with criticisms of his drug war.

Ironically, Duterte is carrying out his own battles with Muslim militants. The Philippine Congress on Saturday approved his appeal to extend martial law in Marawi on the island of Mindanao to the end of the year, the Associated Press reported. The city has been besieged by militants linked to the Islamic State.

In his statement to reporters Friday, Duterte also used the U.S. presence in the Middle East to hit back at McGovern's criticisms.

“It would be good for the U.S. Congress to start with their own investigation of their own violations of the so many civilians killed in the prosecution of the wars in the Middle East. Otherwise I will be forced to investigate you, also. I will start with your past sins,” he said, according to Reuters.

The United States and the Philippines have had a long and storied relationship, dating back to the Spanish-American War. The relationship soured during the Obama administration, after the president criticized the mass killings under Duterte. Not one to take criticism lightly, Duterte snapped at former president Barack Obama on a few occasions, telling him to “go to hell” and, at one point, calling him the Tagalog phrase for “son of a b----” or “son of a whore.” Last September, Obama canceled a meeting with Duterte, whom he called a “colorful guy.”

But the relationship between the two countries had appeared to be shifting with Trump in office. The president praised the war on drugs and invited Duterte to the United States during a phone call in April.

“I just wanted to congratulate you because I am hearing of the unbelievable job on the drug problem. Many countries have the problem, we have a problem, but what a great job you are doing and I just wanted to call and tell you that,” Trump said, according to a transcript of the call obtained by The Washington Post.

Trump also called Duterte “a good man” and toward the end of the conversation, told him that he's “invited anytime” to the White House.

The prospect of the Filipino strongman coming to the United States, however, quickly set off alarm bells among critics, including an international human rights group that advocates for a U.N. investigation of Duterte's administration. Duterte later told reporters that he cannot promise he will accept the invitation, citing his busy schedule.

Duterte's most recent statement appears to be an indication that he's not accepting Trump's invitation.