As the presidents of Colombia, Venezuela, Costa Rica and Latin America's newest democracy, Peru, met last night to draft a statement condemning the recent coup in Bolivia, word reached Lima that Argentina had been the first nation to recognize the new military dictatorship in La Paz.

The timing was not accidental, Argentina's right-wing military government backed the Bolivian coup, two weeks ago and is now providing "technical assistance" to Bolivia's secret police.

In the hope that diplomatic isolation might weaken the resolve of Bolivian Gen. Luis Garcia Meza's government to remain in power, the United States recalled its ambassador and cut off aid.

Bolivia's Andean Pact partners, Colombia, Ecuador, Venezuela and Peru, meanwhile, are leading a diplomatic offensive against Garcia Meza's government.

Argentina, on the other hand, is determined to keep Garcia Meza in power, citing fears that neighboring Bolivia might have become a haven for leftist terrorists if a new left-wing civilian government had come to power as expected on Aug. 6.

As a result of Argentina's support, which reportedly includes a promise of $200 million in economic and military assistance, the issue of the new military regime's survival is pitting South America's democracies to the north against right-wing military governments in Chile, Argentina, Uruguay, Brazil and Paraguay to the south.

[News services reported late Wednesday night that Brazil and Paraguay also had recognized the new Bolivian government.]

In the view of diplomats and government leaders gathered here since Monday's inauguration of Peru's newly elected president, Fernando Belaunde Terry, the Argentine decision to recognize Bolivia's new government was designed to counter the impact of last night's statement here.

Signed by Spain, Costa Rica and Nicaragua as well as Peru, Venezuela, Colombia and Eduador, the statement condemned the Bolivian coup in the strongest terms and left no doubt that the signatories have no plans to recognize Garcia Meza's rule.

The reinitiation of democracy in Peru is an event which fills all democrats in Latin America and the world with pride, optimism and hope," Venezuelan President Luis Herrera Campins said before signing the statement last night. In contrast, he said, "the interruption of the democratic process in Bolivia . . . merits only condemnation."

Colombian President Julio Cesar Turbay Ayala said today that he could envision no circumstances under which his government or the other signatories would recognize the military junta in Bolivia as it presently exists. Ecuador took the formal step of breaking relations with La Paz.

Turbay recalled that a similar strategy of diplomatic isolation contributed to the downfall of Col. Alberto Natusch Busch who seized power in Bolivia last November when he overthrew Walter Guevara Arze.Natusch lasted three weeks.

There is no doubt that President Garcia Meza's government is angered by and worried about the fact that, until yesterday, no country had recognized it and most, including the United States and the Soviet Union, have condemned it.

Garcia Meza said yesterday in La Paz that "we are not obliged to ask permission from Russia, China, Cuba or the United States to do one thing or another. Only Bolivians will decide their destiny."

The new rulers have moved ruthlessly aginst their opponents, claiming that Bolivia was threatened by a "Marxist plot . . . to create another Vietnam in the heart of South America."

Garcia Meza, meanwhile, has said he is prepared to remain in power for 20 years and has warned that "we will be inflexible in applying measures against bad Bolivians who obstruct" the new government.

The question now is whether Garcia Meza's opponents, both inside Bolivia and outside, will also be so inflexible in their opposition as to dislodge the military and encourage civilian rule.

Last night's statement here seems to indicate that a long diplomatic siege lies ahead.