Argentina tells its people war turns grim

After nearly a week of fierce combat in the Falkland Islands, Britain clearly has gained the upper hand.

Guarded Argentine communiques admit as much. Moreover, it appears that the Argentine public is being prepared for this admission.Military spokesmen in Buenos Aires this week were being much more frank about Argentine losses than previously. They admitted a number of airplane losses, although these admissions do not come close to British claims.

Acknowledging their aircraft and major equipment losses, nevertheless, Argentine spokesmen suggested that Argentina may have to go on a military shopping spree to replace lost weapons, airplanes, and ships. This was seen by some as suggesting that Argentina might turn to the Soviet Union for the new equipment.

There were, meanwhile, indications that Argentina might welcome a fresh effort to work out a cease-fire. Foreign Minister Nicanor Costa Mendez at the United Nations Tuesday asked the UN Security Council to find a way to halt the fighting.

But he gave no indication of any new proposals or concessions that might bring Britain to the conference table anew. Further Argentine losses in the conflict and the growing impact on the Argentine public, however, may lead to a more flexible Argentine stance.

The seriousness of the whole South Atlantic conflict was being brought home to Argentines in a variety of ways. They were told Monday that soldiers are now under ''wartime regulations'' and that reservists who have so far failed to report for duty must do so or face stiff prison sentences.

Defense Minister Amadeo Frugoli asserted Monday that ''the situation is getting so difficult that there is the risk not only of the conflict getting worse but also of its becoming internationalized.''

Gone were the haughty assurances of two weeks ago, even one week ago, that the Argentine military muscle would be more than adequate to meet the British challenge. Military prospects look increasingly bleak in Buenos Aires.

But the battle is not over. The British know that. Their flag may again be in place on the islands, but Britain still has a lot of territory to recoup before it can claim effective control of the islands. The British beachhead on San Carlos Bay is a mere 58 square miles - out of the Falklands' total area of 4,618 square miles. And Britain has yet to retake Port Stanley, capital of the islands , where the bulk of Argentina's approximately 10,000 troops are dug in.

Moreover, despite the obvious Argentine difficulties, there should be no underestimating the Argentine resolve to carry on the conflict, nor the Argentine ability to continue inflicting considerable damage on the huge British armada in the South Atlantic. This week's loss of the frigates HMS Ardent and HMS Antelope is clear evidence of Argentina's air might.

How long Argentina can sustain such aerial activity, however, remains to be seen. British missiles and antiaircraft have brought down some 45 Argentine aircraft in recent days - mostly A4 Skyhawks and Mirage IIIs. In addition, Argentina has lost at least 11 other aircraft on the ground. The British Defense Ministry said May 25 its forces had downed three more Argentine Skyhawks that attacked British ships off the Port San Carlos beachhead.

These losses mean that about one-third of the Argentine Air Force has been destroyed. Even more worrisome for military planners in Buenos Aires is the heavy loss of life involved.

Equally troubling the ruling Argentine military junta is the evident low morale of Argentine troops on the Falklands. It has been known all along that Gen. Mario Benjamin Menendez, the Argentine military commander on the Falklands, is worried about the combat readiness of his soldiers and the lack of amenities they face on the islands.

Most are one-year conscripts from Argentina's warm north and therefore unaccustomed to the raw, cold winds that sweep the Falklands and the South Atlantic at this time of year.

For weeks, moreover, reports have circulated in Buenos Aires about the lack of such items as toilet paper and paper tissues on the Falklands. One conscript's letter to his mother on the mainland pleaded that she ''send Kleenex.''

Now with the British on the islands and capturing prisoners, it becomes clear that the Argentine soldiers were poorly fed through the past seven weeks of Argentine occupation of the islands. Stories of eating only once a day are commonplace among the captured soldiers.

Too much, of course, can be made of these stories. But the fact that they persist suggests there must be some truth to them.

They do not, however, minimize the fighting ability of many Argentine units. And British military officials suggest that an Argentine counterattack against the small, but ever-widening British beachhead around San Carlos Bay, some 40 miles west of Port Stanley, is a distinct possibility.

At this writing, no such counterattack has been launched. But May 25 is a traditional Argentine holiday, celebrating the 172nd anniversry of Argentina's independence from Spain. It would be a symbolic occasion for such an attack. (The date incidentally has given its name to Argentina's biggest warship, the aircraft carrier 25 de Mayo, which was reported to be in port due to engine problems - which if true provides further evidence of Argentina's problems with military equipment.)

The British also expect a continuation of the pounding aerial attacks on elements of the Royal Navy by Argentine fighters, but perhaps on a more selective basis than in recent days, when so many Argentine aircraft have been shot down.

Argentina is obviously proud of its Air Force. Brig. Gen. Basilio Ignacio Lami Dozo, the Air Force chief, said as much in a speech this week as he visited Argentine air bases on the mainland from which the raids on the British fleet come. ''They (the pilots) have done themselves and the Argentine nation proud,'' he said.