Al Qaeda's branch in Yemen announced Thursday that four of its members -- including a top cleric believed to be the architect behind the Paris attacks -- were killed in a U.S. drone strike last month in the country's south.

The announcement came amid lingering uncertainty about the impact of Yemen's current political deadlock on the U.S. counterterrorism campaign.

The cleric killed was identified as Sheikh Harith al-Nadhari, said to be in his 30s. Often seen in a white turban, he was among the group's few public faces frequently featured in online religious lectures. He also recently appeared in an Al Qaeda video praising last month's deadly attack at the offices of French satirical weekly Charlie Hebdo.

Al Qaeda in the Arabian Peninsula, as the Yemeni affiliate is known, claimed responsibility for the Paris attack in which two gunmen killed 12 people. Al-Nadhari is believed to be one of the masterminds behind the Jan. 7 attack on Charlie Hebdo, according to Al Arabiya.

Al-Nadhari was killed along with three others on Jan. 31, when a drone-fired missile blew up a vehicle in which the four were traveling in the southern province of Shabwa, according to the AQAP statement, posted on one of its official Twitter accounts.

The Jan. 31 airstrike was the second U.S. drone strike in five days, and was seen as signaling Washington's resolve to keep fighting the militants despite Yemen's political paralysis, brought on by a Shiite rebel power grab.

The attack occurred hours after a written "deal" was struck that gave armed Shiite Houthis control of the Yemeni Capital, sources told FoxNews.com. 

The Shiite Houthi rebels, who are believed to be backed by Iran, overran the capital of Sanaa in September, claiming they want a greater share of power in impoverished Yemen. Last month, they raided key military buildings and the presidential palace, and besieged the residences of U.S.-backed President Abed Rabbo Mansour Hadi and the country's prime minister. The president and his entire Cabinet eventually resigned rather than give in to the rebel demands.

The prospect of a leaderless Yemen has raised concerns about Washington's ability to continue targeting Al Qaeda.

Led by Usama bin Laden's top aide, Nasser al-Wahishi, Al Qaeda's Yemen branch has posed the greatest danger to Western interests, especially the United States. After several unsuccessful operations on U.S. soil, the group claimed the attack on the French magazine, saying it was meant to avenge cartoons depicting the Prophet Muhammad.

Al Qaeda and the Houthis — whose members are mostly Shiite Zaydis — are top enemies and have battled each other in central Yemen. But both groups are also staunchly anti-American, though the Al Qaeda affiliate in Yemen has accused the Houthis of joining ranks with the United States in the war against it.

The Al Qaeda statement vowed the group would continue to target Americans and also Houthis. "You won a battle but not the war ... nothing will stop us," it said.

Al-Nadhari — whose real name is Mohammd al-Murshidi — graduated from the Imam University in Sanaa, a religious school perceived as a bastion of Sunni hard-liners and a recruitment hub for militants. The school is run by cleric Abdul-Majid al-Zindani, who has been designated by Washington as a "global terrorist."

AQAP said in their statement that the killing of Al-Nadhari would not deter their terrorist mission. 

"We will not rest and will not remain silent," the group said. "Neither the killing of a commander nor a hostile bombing will deter us. We consider death for the sake of Allah to be an honor and a virtue, and we yearn for it more than the enemies of Allah yearn for life."

Also on Thursday, the Houthis stormed the headquarters of one of Yemen's biggest newspapers, Akhbar al-Youm, its chief editor said.

Armed men fanned out throughout the offices, locked up journalists in the guards' quarters and took over the papers, said Ibrahim al-Mogahed, the editor-in-chief.

The attackers' intensions were not immediately clear. The paper has been one of the most critical of the Houthi power grab. The rebels last month took over the state news agency.

FoxNews.com's Nadiah Sarsour and The Associated Press contributed to this report.