SAN'A, Yemen - Yemeni security forces stormed an al-Qaeda hideout yesterday in a principal extremist stronghold in the country's west, setting off clashes, officials said, as a security chief vowed to fight the group's powerful local branch until it was eliminated.

A government statement said that at least one suspected al-Qaeda member was arrested during the fighting in Hudaydah province. The province, along Yemen's Red Sea coast, was home to most of the assailants in a bombing and shooting attack outside the U.S. Embassy in 2008 that killed 10 Yemeni guards and four civilians.

"The [Interior] Ministry will continue tracking down al-Qaeda terrorists and will continue its strikes against the group until it is totally eliminated," said the deputy interior minister, Brig. Gen. Saleh al-Zawari.

He was speaking to senior military officials at a meeting in Mareb, one of three provinces where al-Qaeda is believed to have taken shelter.

The group's growing presence in Yemen, an impoverished and lawless country on the edge of the Arabian Peninsula, has drawn attention with the attempted attack on a U.S. airliner on Friday. U.S. investigators said that the Nigerian suspect in the attack told them that he received training and instructions from al-Qaeda operatives in Yemen.

Al-Qaeda in the Arabian Peninsula set up its Yemen base in January when operatives from Saudi Arabia and Yemen merged.

A security official who gave more details on yesterday's raid said that it resulted from a tip and targeted a home five miles north of the Bajil district. He said one suspected al-Qaeda member was injured and several who fled were being pursued.

Also yesterday, more details surfaced about the Nigerian man suspected in the attempted airliner attack. While in Yemen, he led a devout Islamic life, shunning TV and music and avoiding women, said students and staff at an institute where he studied Arabic.

Umar Farouk Abdulmutallab spent two periods in Yemen, from 2004 to 2005 and from August to December of this year, just before the attempted attack, Yemeni officials have said. Administrators at the institute said that he was enrolled at the school during both periods to study Arabic.

Abdulmutallab showed little interest in study during his brief time at the San'a Institute for the Arabic Language this year, which coincided with Ramadan, the holy Muslim month of fasting. It began in late August.

"When I asked him why he wasn't studying, he would tell me he wanted to devote his time for worship during Ramadan," Ahmed Hassan, a 28-year-old Arabic-language student from Singapore, said yesterday.

Hassan said he was stunned when he heard reports that Abdulmutallab, 23, told U.S. officials after his arrest that he received training and instructions from al-Qaeda operatives in Yemen. He said he never suspected the Nigerian of belonging to the terrorist network.

Al-Qaeda in the Arabian Peninsula has claimed responsibility for the attempted attack on the airliner, which was bound for Detroit from Amsterdam. It said it was retaliation for a U.S. operation against the group in Yemen. More than 60 extremists were killed in air strikes this month carried out by Yemeni forces with U.S. intelligence assistance.

Staff and students at the institute said that Abdulmutallab spent at most one month at the school. That has raised questions about what he did during the rest of his stay, which continued into this month.

Ahmed Mohammed, one of the teachers at the institute, said Abdulmutallab spent the last 10 days of Ramadan sequestered in a mosque.

Youssef al-Khawlani, an administrator at the institute, recalled how upset Abdulmutallab was when he heard the ring tone of his phone, set to a popular song.

"When he heard it, he told me I should stop it because it was haram [forbidden by Islam]," Khawlani said. "He also would not watch TV."

Before arriving in Yemen this year, Abdulmutallab studied for a master's degree in international business at a university in Dubai, United Arab Emirates, said the head of the university.

He was quiet and hardworking and showed no signs of extremism during two semesters of study starting in January, said Robert Whelan, the president of the University of Wollongong in Dubai.

"Even with the benefit of hindsight," Whelan said, "nobody can identify anything in his behavior or his interactions through the university that would have been a red flag."