Washington should deploy ground attack aircraft against Muammar Gaddafi's forces and recognize the rebels, leading Senator John McCain said, becoming highest-profile Western politician to visit rebel-held Libya.
Libya's government indicated late on Friday it might adjust its strategy in the besieged city of Misrata, limiting the role of the army and instead sending tribesmen to battle insurgents.
The visit by McCain, the senior Republican politician who ran against Barack Obama for the presidency in 2008, raises the political stakes over a war that the top U.S. military officer acknowledged was headed toward stalemate.
Obama and the leaders of France and Britain say they will not stop their air campaign, now in its second month, until Gaddafi is removed from power. But the bombing has so far failed to tip the balance of power against Gaddafi's forces.
Since the initial days of the strikes, Obama has ordered his troops to take on a backseat military role, reluctant to become embroiled in a third war in a Muslim country and leaving ground strikes to Washington's NATO allies.
This week U.S. forces said they would send drones to carry out ground strikes. In the rebels' eastern stronghold of Benghazi, McCain said Washington should use low-flying attack planes, among the most feared tactical weapons in its arsenal.
"It is still incredibly puzzling to me that the two most accurate close air support weapons systems, the A-10 and the AC-130, have been taken out of the fight," he said on Friday.
In Tripoli, the government's press office said NATO forces had struck the center of the capital early on Saturday. Reuters correspondents did not hear any loud explosions but heard jets fly over the city, rattling windows.
The standoff on the ground has been worst felt in the besieged port city of Misrata, the only large city controlled by rebels in the West of the country, where rights groups believe hundreds of people have died in heavy fighting.
Libyan Deputy Foreign Minister Khaled Kaim said armed tribesmen would be sent to fight in Misrata, reducing the role of the army, in response to air strikes.
He told reporters in Tripoli: "The situation in Misrata will be eased, will be dealt with by the tribes around Misrata and the rest of Misrata's people and not by the Libyan army."
"The tactic of the army is to have a surgical solution but with the (NATO) airstrikes it doesn't work," he said.
Rebels seized control of a downtown office building that had been a base for Gaddafi's snipers and other troops, after a furious two-week battle. Shattered masonry, wrecked tanks and the incinerated corpse of a government soldier lay near the former insurance offices on Friday.
"They shot anything that moved," one fighter said of the Gaddafi men driven out.
In a tent just outside a Misrata hospital, rebel fighter Abdel Salam Daza lay on a stretcher. The doctor treating him said he was probably the victim of a mortar attack because of the multiple wounds to his head, chest and legs.
Daza, trembling, called out: "God is greatest, God is greatest against a tyrant."
There was more sporadic fighting on Friday on Tripoli Street, the main thoroughfare through the city and scene of the fiercest exchanges during the siege, with occasional explosions.
STALEMATE
Admiral Mike Mullen, chairman of the U.S. military's joint chiefs of staff, told U.S. troops in Baghdad that Western-led air strikes had degraded between 30 and 40 percent of Gaddafi's ground forces. Referring to the conflict, he said: "It's certainly moving toward a stalemate.
Obama also described the conflict as a military stalemate last week, but said he thought Gaddafi was being increasingly isolated and would be toppled eventually.
McCain said Washington should recognize the rebels' Transitional National Council as the official government of Libya, a step already taken by France.
"They have earned this right and Gaddafi has forfeited it by waging war on his own people," he said.
White House spokesman Jay Carney, asked about McCain's appeal, replied: "We think it's for the people of Libya to decide who the head of their country is, not for the United States to do that."
Sources close to French President Nicolas Sarkozy said he planned to visit Benghazi, probably in the first two weeks of May, and that he wanted British Prime Minister David Cameron to accompany him.
