SEVERAL leading figures in the Yemeni Socialist Party fear they could be targets for assassination following the murder of Jarallah Omar al-Kuhali, the party's deputy secretary-general.
Jarallah Omar was shot dead by a man armed with two guns as he finished making a speech at a conference organised by the Islah party, which combines tribal, conservative and Islamist elements.
His killer is said to belong to an extremist cell, possibly consisting of five to eight people, which is targeting foreigners and secular Yemenis such as prominent socialists.
A 35-year-old Yemeni who shot dead three American missionaries at a Baptist-run hospital in Jibla, central Yemen, a few days later, is thought to belong to the same group.
Both suspected killers are now under arrest, though the man accused of assassinating Jarallah Omar was not immediately handed to the police.
Instead, he was taken instead to the home of Sheikh Abdullah al-Ahmar, who is leader of the Islah party, speaker of the Yemeni parliament and the country's foremost tribal leader. He was then interrogated on videotape in the sheikh's home, in the presence of representatives from various political parties.
In both cases the suspects appear to have been motivated by extreme religious views, but it is unclear whether they had links to Usama bin Laden.
The small number of Christians in Yemen - almost all of them foreigners - are allowed to worship freely but sometimes attract the attention of Muslim militants who accuse them of proselytising. There are also occasional violent attacks.
A British-built church in Aden was bombed in 2001 and three nuns were shot dead in Hodeidah four years ago - by a veteran of the conflict in Bosnia who was later officially declared insane.
The American Southern Baptists have been working in Yemen for 35 years and their hospital at Jibla has a high reputation for its medical work, though it has sometimes been accused of trying to convert Muslims to Christianity.
The Baptists deny using their hospital to evangelise - at least openly.
"Open evangelism to me is standing on the street corner selling Bibles," Al Lindholm, their chief representative in Yemen, told the New York Times.
"Do we evangelise? No. Are we asked questions about our faith almost daily? Yes, and we answer them as honestly as we know how."
Nevertheless, the website of the Southern Baptist Convention, whose International Mission Board was running the hospital, does make its aspirations clear, urging members to "ask the Lord to raise up strong local churches among the Yemeni".
An American website, pray4yemen.com, also claims that missionary work in central Yemen is bearing fruit.
"After 30 years of Christian outreach, small house churches are beginning to appear," it says. "It is possible that the central Yemeni Arabs could present the first church growth planting movement among the Arabs."
The hospital once included a chapel where Yemenis sometimes came to hear Bible stories and sing songs, but it was closed in 1982 after complaints that the Baptists had converted 200 Yemenis to Christianity.
Despite the controversy about evangelism, news of the murders brought many expressions of sympathy and appreciation from Yemenis in the Jibla area.
One puzzling aspect of the killings is that they came just 48 hours before the Baptists were due to hand over the hospital to a Yemeni (Muslim) charity as part of a cost-saving exercise. This suggests that the killer may not have been seeking to drive the Baptists out but seized a final opportunity to attack them before they left.
Meanwhile, several hundred Yemenis have taken part in demonstrations outside the German embassy in Sana'a, protesting at the arrest of a well-known Yemeni cleric and his assistant for suspected links to al-Qaeda.
In what may have been a CIA sting operation, Sheikh Mohammed Ali Hassan al-Mouyad was reportedly lured to Germany to receive a large charitable donation from an American Muslim - though his family says he merely went there for medical treatment.
The sheikh and his assistant were arrested on January 10 at a hotel near Frankfurt airport on an American warrant and are now held at a maximum-security prison pending a decision on their extradition to the United States.