While Guinea-Bissau's leader was away, did opponents plot a coup?

Officially, nothing untoward happened in Guinea-Bissau while President Joao Bernardo Vieira was in Cuba and Panama for a state visit earlier this month.

But according to some reports from the tiny country on the western bulge of Africa, things did not go well during the President's absence.

A tank commander was killed in the barracks of the country's main armored unit near the capital, Bissau, on March 12.

Guinea-Bissau's embassy in Lisbon called the killing only a ''a minor problem between the military.'' But some wondered if the President's opponents might have been trying to stage a coup.

The question loomed even larger when the diplomatic corps in Bissau went to the airport to welcome the President home March 18 only to find he had returned unannounced the day before.

President Vieira hastily chaired a series of meetings of the country's top bodies to review the internal situation.

A number of officers were reportedly arrested. In the archipelago of Cape Verde -- which until 1980 was ruled by the same party as Guinea-Bissau -- the confused news of the events on the mainland fueled speculation of an attempted coup.

President Vieira himself came to power through a coup in 1980. And some of the problems that served as reasons for mounting his coup -- food shortages and constant power cuts -- are as bad now as they were then. However, the main difference between the two times -- the perceived domination of the Guinea-Bissau/Cape Verde party by Cape Verdeans -- no longer exists. Many of the Cape Verdean elite have fled Guinea-Bissau.

The rift between Cape Verde and Guinea-Bissau left the island without what it considered its military rearguard. With no Army to enforce its will, Cape Verde began to look for as many new friends as possible.

Cape Verde is to send its prime minister to Portugal next month for a meeting of the Socialist International. Cape Verde and Senegal also are drawing closer together.

The coup also required President Vieira to look for new friends. He became his nation's first head of state to visit the Soviet Union and Cuba, which helped his party fight its Portuguese colonial ruler. However, those who know President Vieira caution against casting him in the role of a Kremlin pawn. He has also appealed for help from the West.