The Nicaraguan conflict is an odd one: The guerrillas, by and large, are the former regular army of an ousted Nicaraguan dictator. They wear uniforms, organize their men in a tight rank-and-command structure, and are heavily armed.
These guardsmen-turned-rebels are hunted by a similarly unusual army - an army led by veteran guerrillas, the Sandinistas whose revolution overthrew dictator Anastasio Somoza Debayle.
At this stage in their role reversal, the rebels - called the Nicaraguan Democratic Front (FDN) - appear to have overextended themselves. They had made gains in the past several weeks by penetrating into Matagalpa Province in central Nicaragua, about 70 miles from the capital Managua. But the Sandinista Army this week appears to have blunted their offensive and shut off rebel supply lines. A 200- to 500-man rebel unit reportedly is being driven out of Matagalpa.
Sporadic combat continues in northern sections of the country, however. Rebels there can be resupplied by their bases across the border in Honduras. And the FDN is reportedly regrouping for a new thrust south of the northern region.
Early this week, Nicaragua sent its Air Force against the rebels for the first time, bombing an airstrip the FDN had built in northern Jinotega Province. The Sandinistas recently showed hundreds of weapons they said they had captured this month - Chinese rifles, M-16 automatic rifles, and one-shot disposable rocket launchers. The M-16s and rocket launchers were marked as property of the US Army.
Nicaraguan Interior Minister Tomas Borge told reporters that he believes the United States is seeking to create the image of a civil war inside Nicaragua in order to equate it to the war in El Salvador. Then, he suggested, the US may offer negotiations of both the Nicaraguan and Salvadorean conflicts.
He notes that the US repeatedly charges that Nicaragua is supplying weapons to the Salvadorean guerrillas. ''We have asked to see proof of arms shipments from Nicaragua to El Salvador but we have never seen them,'' he says.
He admits that Nicaragua's Sandinista leaders would like the Salvadorean rebels to win their war, and that President Reagan wants the Salvadorean government troops to triumph.
''But to get back to earth,'' he said, ''a political solution must be found that will not completely fulfill the desires of the revolutionaries nor fulfill the desires of the enemies of the Salvadorean people. A formula has to be found to stop this terrible drama in the interests of the people.''
At the same time, Nicaraguan officials have lashed out at the US, accusing it of arming, paying, training, and planning the FDN's counterrevolutionary attacks.
Commenting on Reagan's televised display of an aerial photo of Managua's commercial and military airport, one Sandinista said, ''Airlines passengers get a better view'' of the three Soviet helicopters there.
Many Nicaraguans fear the FDN rebels. But some welcome them. An Army officer in Jalapa said that some villagers are sympathetic to the FDN because many of their sons had joined the national guard and are now in jail, dead, or in exile.