In the rocky hills 40 kilometers south of the capital city, Sana, a small group of Palestinian commandos wearing new boots and new uniforms form three neat lines and count in unison as they complete their afternoon training.
Most of the men appear to be in their 20s, but one of them could easily be 12 or 13 years old. They are all veterans of last summer's Israeli siege of Beirut.
Now a long way from Palestine, exiled in this remote corner of the Arabian Peninsula, they are, nonetheless, attempting to keep their ''revolution'' against Israel alive.
Palestinian officials say most of the Palestine Liberation Organization (PLO) guerrillas who came to North Yemen as a part of the United States negotiated evacuation of PLO fighters from Beirut are still here.
They live in a tent camp nestled in the hills off the Sana-Taiz highway, where they daily do exercises and hold training and strategy sessions. The camp consists of about 25 large tents and two, two-room cinder-block office buildings. It is ringed by a simple wire fence - no barbed wire. There are a half dozen guard dogs. The flags of both North Yemen and Palestine are displayed throughout the camp, as are portraits of both Yasser Arafat, the PLO leader, and Ali Abdullah Saleh, the President of North Yemen.
At the time of the evacuation it was estimated that more than 400 fighters traveled by ship to North Yemen. PLO officials say 31 of these men have since left for Syria; a few others were transferred for medical reasons to other countries with more sophisticated hospitals. In addition to the PLO men, Palestinian officials say 64 women and 142 children sailed in the evacuation ship from Beirut.
One who has stayed since arriving in early September is 20-year-old Zahra Abdul Hamid. On Aug. 29, Zahra put on a pair of PLO fatigues and followed her husband out of Beirut and onto the ship that would take them to North Yemen.
She left her mother, father, sister, and brother behind in the Sabra Palestinian neighborhood in Beirut. She has heard nothing of them since. She does not know whether they were caught in the September massacre in the Sabra and Shatila camps.
Some of the Palestinians in the camp blame themselves for leaving their families and other civilian Palestinians defenseless in Beirut. They also blame the US government for failing to live up to the promise to protect the civilian Palestinians who remained in Beirut.
But the massacre is also a rallying point. During his visit here two months ago, Yasser Arafat officially named this military camp ''Sabra,'' after one of the sites of the Beirut massacre. A similar evacuation camp near Aden, South Yemen, was named Shatila.
PLO commanders say they are preparing their men to better defend the Palestinians against Israeli attack. They say they are not training for an attack on Israel.
Such statements are partly designed for consumption in the United States. The officials stressed that they felt it was important that the American people - as well as the US Congress and the Reagan administration - understand the problems of the Palestinians. The camp docter said repeatedly that the Palestinians want peace, not war, and that the Palestinians are like any other people - they just want a safe home in a country of their own.
Zahra says without emotion that she does not mind the stay in North Yemen. She adds, also without emotion, that she has no intention of returning to Beirut.
''What do I have in Beirut?,'' she asks. She says she intends to go ''from here to Palestine - direct.''
The camp commander, a PLO military officer for 22 years who identified himself only as Colonel Ahmed, said he didn't know how long his men would remain in North Yemen - ''maybe one month, maybe two years.'' He said that 10 days earlier his wife and children had arrived in Sana. The government was providing housing for them there.
He said he and his men would remain in the camp until they received orders from the PLO to go elsewhere.
In the meantime, the camp's residents continue to train in military tactics and strategy, and broadcasts over the camp loudspeaker system talk of battles, revolution, and struggle. It is an effort to ensure that the men will be ready, if needed, and that the cohesion of the PLO military will not be lost in the dispersion of its men throughout eight Arab countries.
''We have just lost one of our positions,'' Colonel Ahmed says, referring to the PLO evacuation from Beirut. He adds, ''We are about 5,000 outside the area [ the vicinity of Israel] but at the same time we are 4 million in the area.''