The Egyptian army secured Cairo's famed antiquities museum early today, protecting thousands of priceless artefacts, including the gold mask of King Tutankhamun, from looters.

The greatest threat to the Egyptian Museum, which draws millions of tourists a year, first appeared to come from the fire engulfing the ruling party headquarters next door, set ablaze by anti-government protesters.

Then dozens of would-be thieves started entering the grounds surrounding the museum, climbing over the metal fence or jumping inside from trees lining the sidewalk outside.

One man pleaded with people outside the museum's gates on Tahrir Square not to loot the building, shouting at the crowd: "We are not like Baghdad."

After the 2003 US-led invasion of Iraq, thieves carted off thousands of artefacts from the National Museum in Baghdad - only a fraction of which have been recovered.

Suddenly other young men - some armed with truncheons taken from the police - formed a human chain outside the main entrance in an attempt to protect the collection inside.

"I'm standing here to defend and to protect our national treasure," said one of the men, Farid Saad, a 40-year-old engineer.

Another man, 26-year-old Ahmed Ibrahim, said it was important to guard the museum because it "has 5,000 years of our history. If they steal it, we'll never find it again".

Finally, four armoured vehicles took up posts outside the massive coral-coloured building in downtown Cairo.

Soldiers surrounded the building and moved inside to protect mummies, monumental stone statues, ornate royal jewellery and other pharaonic artefacts.

The soldiers appeared to have rounded up all the would-be looters who made it onto the museum grounds and had lined them up in a row.

As the soldiers corralled one man toward the line, crowds outside the fence shouted, "Thief, thief!"

A couple of the troops then hit the man with the butts of their rifles and sat him down with the others apparently caught inside.