"Scores" of Muslim militants with suspected terror links have been arrested during a search for a terrorist cell targeting foreigners and secular-minded politicians, a security official said Wednesday.The arrests followed the weekend assassination of veteran leftist politician Jarallah Omar and the Monday killings of three American missionaries in southern Yemen. Both attacks were committed by suspected Muslim extremists.

Omar, deputy secretary general of the Socialist Party, was buried Wednesday in the capital, San'a, amid tight security measures.

The security official, speaking on condition of anonymity, said authorities hope the militants' arrests will lead them to a terrorist cell plotting attacks on foreigners and secular-minded politicians. He declined to give the number of those arrested, saying only there were "scores of suspects."

Another official, also speaking on condition of anonymity, told The Associated Press that security measures were beefed up around foreign embassies and major hotels in San`a for fear of possible terrorist attacks. He did not elaborate.

The existence of the alleged cell was revealed in confessions by Abed Abdul Razak Kamel, the main suspect in the killing of the three American missionaries in a Baptist hospital in Jibla, 125 miles south of San'a, Yemeni officials said.

On Tuesday, officials close to the investigation said Yemeni interrogators suspect Kamel has connections to Osama bin Laden s terror network. Yemen is bin Laden's ancestral homeland and has been a fertile recruiting ground for his al-Qaida organization.

Pharmacist Donald W. Caswell, 49, of Levelland, Texas, who was wounded in the Jibla shooting, left the hospital Tuesday after treatment for abdomen wounds, a U.S. diplomat said on condition of anonymity.

Caswell and other Americans who worked at the Jibla hospital were driven to San'a in U.S. Embassy vehicles, the diplomat said.

Meanwhile, an FBI  team has been in Jibla since Monday but U.S. diplomats refuse to say whether its members were allowed to question Kamel directly. However, they said the Americans "are very close" to the interrogation.

During past investigations of attacks on U.S. targets here, Americans working alongside Yemenis have complained of having limited access to suspects.

While the U.S. Embassy said it was too early to tell if terrorism was behind the Jibla shooting, Yemeni Prime Minister Abdul-Kader Bajammal included the slayings in a list of terrorist acts he presented to parliament Monday.

Bajammal accused "extremist elements in several (Yemeni) parties of having links with al-Qaida." He did not elaborate.

In the Jibla attack, a gunman slipped into the hospital cradling his hidden gun like a baby. He entered a room where the director was conducting a meeting and opened fire at about 8:15 a.m. Monday, officials and witnesses said.

After shooting three people in the head, killing them instantly, the gunman headed to the pharmacy and shot Caswell in the abdomen.

The International Mission Board of the Southern Baptist Convention identified the dead as purchasing agent Kathleen A. Gariety, 53, of Wauwatosa, Wis.; Dr. Martha C. Myers, 57, of Montgomery, Ala.; and hospital director William E. Koehn, 60, of Arlington, Texas.

Gariety's body was to be flown to the United States. Myers and Koehn, who each spent more than two decades in Yemen as missionaries, were buried Tuesday in a missionary cemetery on the hospital grounds.

The official news agency Saba quoted an official saying the suspect told interrogators he plotted the attack in collaboration with Ali al-Jarallah, who Yemeni officials say is a Muslim extremist and member of the fundamentalist Islamic Reform Party. He was arrested for shooting Omar dead on Saturday.

Tens of thousands of Yemenis on Wednesday escorted the veteran politician's body to its final resting place at the Martyrs' Cemetery in San`a. The burial was attended by a representative of President Ali Abdullah Saleh and was held under heavy security.

Yemen long has tolerated Muslim extremists, who take refuge in its lawless tribal strongholds. It has been a key front in the U.S.-led war on terrorism and its government signed on as Washington's partner after the Sept. 11 attacks.

Like elsewhere in the Arab world, anti-American sentiments are running high in Yemen over Washington's perceived support for Israel and its standoff with Iraq.

The United States has stepped up its military presence in the region following the 2000 bombing of the USS Cole  off Yemen by an explosive-laden boat. The attack, blamed on al-Qaida, killed 17 U.S. sailors.

In November, a CIA -operated Predator drone fired a missile that killed bin Laden's top lieutenant in Yemen, Qaed Salim Sinan al-Harethi, and five other al-Qaida suspects.

PHOTO CAPTION

Yemeni people carry the coffin of Jarallah Omar during his funeral, in San'a on Wednesday, Jan. 1, 2003. Omar, deputy secretary general of the Socialist Party, was shot dead last Saturday by Muslim extremists. (AP Photo/Jamal Nasrallah)