Mexico City — As T-61 tanks took up positions around Managua this week, and military mobilization increased throughout the country, Nicaragua's government is again alerting its people to what it sees as a possible US invasion. This has happened several times before and most Nicaraguans have grown jaded about such warnings.
This time, however, the general level of anxiety is deeper because of the US Congress's recent vote to restore aid to the anti-Sandinista rebels, known as ``contras,'' according to sources in Managua close to the ruling Sandinista Party. The government of Daniel Ortega Saavedra views this vote as marking a new level of US commitment to the contras.
Sandinista anxieties are further heightened, according to sources close to them, by current US frustration over its inability to resolve the hostage crisis in Lebanon and the recent shooting of four US marines in El Salvador.
``The last time Reagan was frustrated about events in Lebanon [after the car-bombing in Beirut that killed 241 US marines], he invaded Grenada,'' said one of these sources. The bombing occurred on Oct. 23, 1983. The US invasion of Grenada came two days later.
Nicaraguans are concerned that the US allegedly accused their country of promoting terrorism in El Salvador, following last week's attack on US marines.
The Sandinistas fear that events in Lebanon and El Salvador could help create a general climate of opinion in the US that the Reagan administration might interpret as justification for an invasion.
At the same time Nicaragua is continuing to seek the support of the members of the Contadora group. The Contadora countries -- Mexico, Panama, Venezuela, Colombia -- are trying to arrange a peaceful settlement in Central America.
Nicaraguan Vice-President Sergio Ramirez left this week for visits to the Contadora nations, as well as to Uruguay, Brazil, and Peru in an effort to gather support.
The Sandinistas hope that increased participation by South American countries like Brazil and Peru in the Contadora process will counterbalance the influence of what they perceive to be US-dominated countries like Costa Rica and Honduras.
Ramirez's trip occurs a week after Nicaragua walked out of a Contadora session when the members refused to change their agenda and discuss a proposed response to the renewal of US aid to the contras.
Recent US press reports have included statements by US intelligence sources stating that a great majority of the Nicaraguan population would welcome a US invasion.
According to one source, the Nicaraguans are carrying out large popular mobilizations in order to show these US analysts that, ``they are making a mistake.''