World Notes Central America

While they may never be fast friends, Nicaragua and Costa Rica moved last week to ease the border tensions that threatened to destroy their already edgy relations. The two countries agreed to form a joint patrol of their 225-mile frontier to prevent clashes between Sandinista forces and U.S.-backed contras based in Costa Rica. The arrangement is designed to avoid incidents like the shooting deaths of two Costa Rican guardsmen last May, which resulted in abruptly severed diplomatic relations. Reason: San Jose blamed the violence on Sandinista troops, while Managua blamed the contras.

The border agreement follows the election last month of Costa Rican President-elect Oscar Arias Sanchez. Shortly after his victory, the feuding neighbors resumed relations and exchanged new ambassadors. Nicaraguan President Daniel Ortega Saavedra was quick to portray the accord as evidence of his country's desire for peace in the region. The Reagan Administration, which last week asked Congress for an additional $100 million in aid for the contras, was unimpressed. Said a State Department spokesman: "It's nice they're having these bilateral accords, but they can't take the place of a regional, verifiable settlement."