KABUL, Afghanistan (AP) _ The nation's only museum, destroyed and looted, is the latest casualty in a 14-year-old civil war that has obliterated countless symbols of a varied heritage as old as mankind.

Across Afghanistan, archaeological sites and ancient monuments have been blown to pieces.

''Future generations will never forgive us for this vandalism,'' said Najibullah Popal, who had been curator of the National Museum of Kabul for 18 years. ''If this goes on, nothing will remain of Afghanistan's heritage. We will have no history left.''

There are no records of the devastation, but Popal estimates more than half of Afghanistan's archaeological and historical sites and monuments have been destroyed or damaged.

For his museum, the end came when rival guerrilla factions started fighting last month. In just 12 days, the building was reduced to rubble. Of its tens of thousands of artifacts, some as old as 100,000 years, many were destroyed and others were stolen.

War came to Afghanistan when Soviet soldiers arrived in 1979 to prop up a Moscow-sponsored Communist regime and met resistance from Islamic fundamentalist guerrillas. The Red Army left in 1989, under an international agreement, and the regime it left behind collapsed last year.

With the common enemy gone, major guerrilla groups began fighting among themselves.

The lost treasures trace the history of one of the world's great crossroads. For 2,500 years, Persians, Greeks, Indians, Turks and Mongols traveled, traded and ruled in Afghanistan. All left imprints to be discovered by archaeologists.

It was through Afghanistan that Alexander the Great launched his conquest of India 2,300 years ago. Then came Hindu conquerers from India. Buddhism crossed the mountains from India to China, Mongolia and Korea. After the Arabs brought Islam 1,300 years ago, the Mongols swept down from the northeast.

Of several monuments to Buddhism, one of the finest was a site at least 1,200 years old that had been excavated and preserved in Hadda, an eastern city. It was destroyed in battles with the Red Army, Popal said.

Relics of the various civilizations were displayed in the 63-year-old National Museum, which Popal closed in 1990 when the Communist regime seemed about to fall.

Most of the artifacts were packed up and stored in the basement. That protected them from frequent rocket attacks on the museum between May 12 and May 23, but valuable pieces apparently were stolen by the fighters.

A few miles from the museum is the Babur Shah garden, laid out by the 16th century Muslim emperor on the slopes of Sher-i-Darwaza mountain.

The garden had been a favorite picnic spot for families from Kabul. Four weeks ago, it was a battleground.

When the fighting stopped, the boundary wall was a heap of loose clay bricks. The parking area was strewn with shell casings and twisted remnants of spent rockets.

Inside Babur's garden, trees felled by mortar fire lay across each other. The bark of others was chipped by bullets and branches had been cut for firewood by fighters camped in a 90-year-old pavilion hit by shellfire.

Some in the government show increasing concern for the destruction of history, but most of the illiterate mountain fighters care little.

''The situation is very sad,'' said Ghulam Saki Mesbah, deputy culture minister. ''It's a mess.''

Nesbah said the government wants to set up a commission of all guerrilla groups to protect the monuments, but that it would not be possible for months.

Until then, what is left of the museum is open to plunder by anyone with a gun.

Many crates of exhibits have been broken open and emptied.

In one corner lies a shattered marble statue of the Hindu goddess Durga executing a bull with a man's head. On one of the gutted upper stories is a room stacked with soot-blackened metal pots, jars and urns.

''The guerrillas think the museum is just a place to keep statues,'' Popal said, tears coursing down his cheeks. ''They should know it is the heart of our country and a most eloquent part of the world heritage.''