BEIJING — China escalated its opposition to American-led airstrikes on Libya on Tuesday, joining Russia and India in calls for an immediate cease-fire and suggesting that coalition forces were imperiling civilians by exceeding the United Nations-mandated no-fly zone.

The rising criticism among the so-called BRIC group — Brazil, Russia, India and China — came amid allegations by the Libyan government that allied bombings had killed or wounded scores of civilians, a claim rejected by American military officials.

On Monday, hours after the departure of President Obama, Brazil issued a statement condemning the attacks and urging “the start of dialogue.”

China’s response to the campaign has been the most forceful, warning that the assault could bring about a “humanitarian disaster.” In a news briefing Tuesday, Jiang Yu, a Foreign Ministry spokeswoman, called for an end to hostilities. “We’ve seen reports that the use of armed force is causing civilian casualties, and we oppose the wanton use of armed force leading to more civilian casualties,” she said.