Artillery exchanges and skirmishes between British and Argentine front-line troops continued near the Falkland Islands capital of Stanley today as both sides awaited the final assault by British forces.

While reports from Argentina suggested the attack may be delayed two weeks by heavy British losses suffered from Argentine air attacks earlier this week, the Defense Ministry here said British forces "continued to consolidate positions and move equipment forward" for the decisive battle.

Both sides claimed to have caused small numbers of casualties in what the Defense Ministry here called "aggressive" British patrolling of contested ground between the two front lines, which are less than five miles apart at some points.

A pessimistic message to the Argentine military command in Buenos Aires from the Stanley garrison commander, Brig. Gen. Mario Benjamin Menendez, was monitored in the last 24 hours from Chile, according to a British Broadcasting Corporation correspondent in Punta Arenas, a Chilean city at the southern tip of South America 500 miles west of the Falklands.

Menendez reported a drop in the morale of his troops because of the virtual British siege, BBC correspondent Brian Barron said, quoting Menendez as saying in the intercepted message: "If things go on like this, our situation could crumble rapidly."

Barron, in a dispatch from Punta Arenas broadcast on national television and radio here today, reported that "the dispirited tone of the brief message is a complete reverse of the Argentine commander's exuberant, confident exchanges monitored here a month or more ago."

Independent analysts here said they had no reason to doubt the validity of the report because earlier messages between Stanley and Buenos Aires had been similarly monitored by what Barron called "specialist sources" in southern Chile near major military bases across the border in Argentina.

In Buenos Aires, the Argentine military command accused British warplanes of firing two missiles at an Argentine hospital ship carrying wounded and a commission from the International Red Cross off shore from Stanley. A communique said the missiles missed the ship, but one struck a house on shore, Washington Post correspondent Jackson Diehl reported.

The communique said that Argentina had protested the incident through diplomatic channels. A military spokesman also said tonight that a British warship bombarded Stanley at dawn and that two British Harrier warplanes later attacked Argentine positions at Stanley.

Meanwhile, British spokesmen continued their refusal to disclose the extent of British casualties in Tuesday's Argentine air raids on landing ships putting ashore Scots and Welsh guards of the Fifth Infantry Brigade at Fitzroy and Bluff Cove, 15 miles southwest of Stanley.

British sources suggested today that more than 50 but less than 100 British troops and seamen were killed when two landing ships, a frigate and a small landing craft were hit by bombs from Argentine Mirage and Skyhawk fighter-bombers. Reports from Buenos Aires have suggested the toll could run into the hundreds.

Political sources here said the final casualty figures may be announced Saturday. But military sources said the commander of the British ground forces on the Falklands, Royal Marine Maj. Gen. Jeremy Moore, specifically requested that the figures be withheld so Argentine commanders would not know what impact the losses might have on the timetable or tactics of the British forces.

The British Defense Ministry said today there have been no further "sustained air attacks" by Argentina since Tuesday, "although the weather was fine and clear" in the Falklands.

"Four Argentinian Mirage aircraft were seen by the British naval task force. Two turned back when intercepted, and two flew low and were lost to contact," the ministry said. "No further air engagements took place until yesterday, when four Argentinian Pucras strafed one of our forward positions. There were no British casualties."

This would suggest that Argentine forces somewhere on the Falklands, perhaps on West Falkland, are still able to mount sorties with the low-flying, short-range ground attack planes. The monitored message from Menendez indicated that the Stanley garrison was now sufficiently cut off from air and other contact with the mainland to prevent any supplies or reinforcements from getting in and troops from getting out.

Based on Defense Ministry and British correspondents' reports of military activity on the Falklands through Thursday, the main body of British forces was still being moved with its equipment into position for an assault on Stanley, while patrols of up to 30 Marines or paratroopers continued to probe Argentine front-line positions.

British war correspondents reported that some of these patrols moved to within a few hundred yards of some Argentine positions to observe them without engaging them in battle. When one British patrol clashed with Argentine troops Wednesday, the Defense Ministry said today, "five Argentinians were killed and there were no British casualties."

The Argentine military has claimed that four British soldiers were killed and one taken prisoner in similar encounters.

Two British war correspondents, Leslie Dowd of Reuter and Charles Laurence of the Sunday Telegraph, said in dispatches filed earlier this week that British troops on high ground west of Stanley had become impatient to begin the final assault after a week of wind, rain and freezing temperatures before the weather cleared.

"What has been going on last week is the steady and determined buildup of the largest and most comprehensively equipped assault force that Britain has mustered for 30 years," Laurence reported. "Hundreds of tons of artillery ammunition has been flown up, dangling in cargo nets from the bellies of Sea King and Wessex helicopters, thousands of mortar rounds and steel box after steel box of rifle and machine-gun rounds."