Foreign Ministry spokeswoman Jiang Yu said Beijing wants an immediate cease-fire and seeks a peaceful resolution to the conflict. China, like fellow critic Russia, abstained from backing the U.N. resolution authorizing the attacks, but did not veto the measure.

The Arab League, which initially supported the U.N. move, has also expressed reservations. All say they are concerned about possible civilian casualties and a humanitarian crisis - exactly what the measure aims to prevent.

Speaking in Moscow, U.S. Defense Secretary Robert Gates questioned those concerns.

"It's perfectly evident that the vast majority, if not nearly all civilian casualties have been inflicted by Gadhafi," said Gates. "Most of our targets, virtually all of our targets are isolated, non-populated areas."

He called Colonel Moammar Gadhafi's claims of civilian casualties "outright lies." Libyan officials say dozens of people have been killed in coalition attacks, which began Saturday. Those figures have not been independently confirmed.

A Tripoli resident, who prefers to give just his first name, Ali, said by telephone Tuesday that much of the capital was functioning normally.

Ali said the situation is good: the shops are open, there is traffic. He adds he has not been out of the capital, but in Tripoli, it's fine.

The effort to set up the no-fly zone appeared to be helping the rebels in the east. Opposition forces had been pushed out of territory it once claimed, with fighting Saturday reaching the de facto rebel capital, Benghazi. The rebels have since been pushing back, and were engaged in heavy ground fighting with pro-Gadhafi forces Tuesday near the town of Ajdabiya.