MONROVIA, Liberia ? Liberian rebels darted across contested bridges to shake hands Tuesday with government fighters — many as young as 10 and barely bigger than their AK-47s — as a steadily building West African deployment brought an edgy day of calm to Liberia’s gutted, looted capital.

International aid agencies sped aid shipments to Monrovia, bloodied by two months of rebel sieges that have killed more than 1,000 civilians and cut the capital off from food, clean water and all but the barest medical care.

Pallets with tons of relief aid piled up at Liberia’s main airport as white U.N. helicopters shuttled in Nigerian troops of a promised 3,250-member West African deployment.

It will be days before the peace troops move from the airport into the capital, but their mere presence in the country was enough to still AK-47s in the war-divided city.

Two U.S. warships with Marines were waiting out of sight offshore.

Though the United States said Americans would deploy only after President Charles Taylor leaves, a senior administration official said late Tuesday that President Bush has authorized a contingent of six to 10 U.S. troops to enter Liberia as early as today to provide logistical support for West African peacekeeping forces.

The official, who spoke on condition of anonymity, said the team could grow to as large as 20 in coming days.

“My brother, what are we fighting for?” declared rebel commander Gen. Acapulco as he embraced government Col. George P. Rollins on Monrovia’s New Bridge.

Target of repeated rebel pushes toward President Charles Taylor’s downtown stronghold, the bridge and two others leading from the rebel-held port had been a killing zone for two weeks, raked by mortar rounds, rockets and automatic weapons fire.

“I have no problem with you, my brother,” said Acapulco, who wore a T-shirt proclaiming, “I want to be a millionaire,” shaking the officer’s hand. “We are only against one person. That is Charles Taylor.”

At one point, three lower-ranking rebels darted across the bridge, shaking hands with their government rivals before running back.

U.S. Ambassador John Blaney was among those traveling to the rebel side in a convoy with West African force officials.

In a building with tarps hung across shattered windows, they appealed to rebels to open the port for humanitarian access.

Rebel chief of staff Maj. Gen. Abdulla Seyeah Sheriff told reporters that would happen only when Taylor resigned and left Liberia.

Later, Taylor’s military chief of staff, Gen. Benjamin Yeaten, warned that if rebels fail to withdraw from the port it could “tempt me” to break the cease-fire.