BY GLENN GARVIN

 MANAGUA -- Central America's spreading border disputes took a rancorous turn
 Thursday with the announcement that Nicaragua, El Salvador and Guatemala will
 sign a secretly negotiated trade agreement today that pointedly excludes Costa
 Rica and Honduras.

 No details were released of the agreement, hammered out in secret meetings
 between the presidents over the past two months at a Nicaraguan beach resort.

 But Nicaraguan President Arnoldo Aleman said it would set firm deadlines for the
 three countries to lower trade barriers for one another's goods.

 Asked if the agreement was an attempt to isolate Costa Rica and Honduras,
 Aleman would say only: ``This is an alliance between Central Americans for
 Central America.''

 Diplomats, though, said the deal was a deliberate snub in retaliation for what the
 other three countries see as land grabs by Costa Rica and especially Honduras.

 Not only has Honduras been fighting with all three of its neighbors over maritime
 boundaries, but last month began rigorously enforcing customs laws that slowed
 delivery of goods all over Central America.

 ``Everybody's furious at Honduras,'' one diplomat said. In an effort to soften the
 blow to Costa Rica, Guatemalan President Alfonso Portillo traveled there
 Wednesday to give the country's president, Miguel Angel Rodriguez, advance
 word that the pact would be signed.

 Nonetheless, diplomats and economic analysts said the revelation of the secret
 agreement was a discouraging sign that, at a time when most of the rest of the
 world is trying to integrate its economies, ancient political feuds are pushing
 Central American governments farther apart.

 Border disputes have flared during the past two years from the northern tip of
 Central America, where old tensions between Guatemala and Belize have been
 renewed, to the southern tip, where Colombia's civil war has spilled over the
 mostly unmarked frontier into Panama.

 The noisiest disputes have been among the five countries most affected by
 Thursday's announcement. Honduras has squabbled with Guatemala and El
 Salvador over the maritime boundaries in the Gulf of Fonseca on the Pacific side
 of the isthmus, and has ratified a treaty with Colombia on the Atlantic side that
 Nicaraguan claimed violated its rights.

 The argument between Honduras and Nicaragua got so heated that both countries
 began moving troops toward the border late last year before the governments
 agreed to settle the dispute in the World Court. Meanwhile, tempers erupted
 between Costa Rica and Nicaragua over the San Juan River, which forms the
 border between them.

 The wrangling over borders has set back efforts by the five countries to form a
 Central American common market.