SINGAMARAJA

TRIPOLI, Libya – After dramatic successes over the past weeks, Libya's rebel movement appears to have hit a wall of overwhelming power from loyalists of Moammar Gadhafi. Pro-regime forces halted their drive on Tripoli with a heavy barrage of rockets in the east and threatened Tuesday to recapture the closest rebel-held city to the capital in the west.

If Zawiya, on Tripoli's doorstep, is ultimately retaken, the contours of a stalemate would emerge — with Libya divided between a largely loyalist west and a rebel east as the world wrestles with the thorny question of how deeply to intervene.

President Barack Obama and British Prime Minister David Cameron agreed to plan for the "full spectrum of possible responses" on Libya, including imposing a no-fly zone to prevent Gadhafi's warplanes from striking rebels. According to a White House statement, the two leaders spoke Tuesday and agreed that the objective must be an end to violence and the departure of Gadhafi "as quickly as possible."

A spokesman for the opposition's newly created Interim Governing Council in Benghazi, meanwhile, said a man who claimed to represent Gadhafi made contact with the council to discuss terms for the leader of four decades to step down. Mustafa Gheriani told The Associated Press the council could not be certain whether the man was acting on his own initiative or did in fact represent Gadhafi.

"But our position is clear: No negotiations with the Gadhafi regime," said Gheriani, who declined to say when contact was made or reveal the identity of the purported envoy. Libyan state television denied that Gadhafi had sent an envoy to talk to the rebels.

In London, British Foreign Secretary William Hague said that neither Gadhafi nor rebel forces appeared currently able to establish supremacy. "At the moment ... it seems that either side lacks the immediate power to overthrow the other," he said.

Later Tuesday, Gadhafi made a surprise appearance at a hotel hosting foreign correspondents in Tripoli, arriving just before midnight. He raised his fist in the air as he walked from his car to the hotel, then he went into a room separated by curtains for exclusive interviews with a Turkish and a French television station.