The Bush administration called the slaying of three American missionaries Monday in Yemen despicable, but did not brand it an act of terror, and praised Yemeni authorities for quickly arresting a suspect.

Yemeni President Ali Abdullah Saleh condemned the shooting at Southern Baptist Hospital in Jibla as criminal and disgraceful and pledged to punish the perpetrators, the official news agency Saba reported.

Yemen long has been a haven for Muslim extremists and is the ancestral home of Usama bin Laden, the Saudi exile whose Al Qaeda network is believed responsible for the Sept. 11 terror attacks.

A suspected Muslim extremist was arrested by Yemeni authorities for the attack on the hospital, which also wounded a fourth person. "We are working closely with them to investigate the attack," said Philip T. Reeker, a State Department spokesman.

"It's a horrible crime, but we have to let the investigation go forward and make that determination" whether terrorists were involved, Reeker said.

"The fact that they have already arrested a suspect in the case is a good start," he said.

U.S. consular and security officials were sent from the U.S. Embassy in San'a to Jibla to check the security of other Americans, Reeker said.

Reeker said the U.S. Embassy was functioning at full capacity, although young dependents were not permitted to join their parents there. The department again advised U.S. citizens to avoid nonessential travel to Yemen.

The spokesman called Yemen a dangerous place in a dangerous neighborhood and said the 30,000 U.S. citizens, many of them holding dual citizenship, should "take prudent security measures, try to avoid crowds and vary times and routes of travel."

The Bush administration has strengthened relations with Yemen, shared intelligence with its officials and praised its counter-terror program.

"We certainly continue to work with Yemen and thank them for the efforts they've made in fighting terrorism," Reeker said.

In October 2000, the U.S. destroyer Cole was attacked in a suicide bombing in Yemen and 17 American sailors were killed. Al Qaeda was considered responsible, but the investigation, which was left primarily in the hands of Yemen, has not solved the crime.

Last month, Abd al-Kareem al-Iryani, an adviser to President Saleh, confirmed funds were flowing from Saudi Arabia and other countries to extremists in Yemen.

"No Arab government supports extremists," he said, "but there is money in the world coming to these people."

In Crawford, Texas, where President Bush was on vacation, White House spokesman Scott McClellan also condemned the slayings and said the missionaries "were providing humanitarian assistance to the Yemeni people."

McClellan said U.S. investigators were working closely with their Yemeni counterparts "to bring to justice all those who are responsible." He said he did not know whether more than one suspect was involved.