TRIPOLI, Libya – Libyan rebel forces made major advances in Misrata on Wednesday, capturing the strategically important airport and large swaths of territory around a city that has been encircled by Libyan troops, residents and rebel officials said.

The fight over Misrata has been the bloodiest battle in the nearly three-month conflict, and the rebel gains come as NATO has increased the intensity of its bombardment and its coordination with rebel officials.

A leader of the Libyan opposition council, Mahmoud Jibril, said Wednesday that NATO had established a line of communication with rebel commanders in Benghazi, enabling them to improve the effectiveness of their strikes.

“There is direct contact between the operations room in Benghazi and NATO headquarters,” Jibril told reporters and editorial writers in a visit to The Washington Post. “The coordination is much, much better than before.”

Residents of Misrata contacted via Skype said that many in the city turned out into the streets to celebrate on Wednesday evening, with honking cars replacing the sounds of rocket shells after government forces were pushed out of range of most of the city.

Mohammed Alzawwam, a rebel spokesman in Misrata, said that rebels had captured stores of ammunition and vehicles that Libyan government troops apparently left behind.

“This doesn’t make the city totally safe, but it makes it safer,” said Mohamed, a member of Misrata’s local council, who asked that his full name not be used to protect his safety. “This is the third day of extensive fighting in and around the airport.”

He said rebels captured about 40 miles of territory west of the city, Libya’s third largest, and about 23 miles toward the east. He said that Misrata’s port, a crucial supply point that had been under siege from forces loyal to Moammar Gadhafi, was now significantly safer.

Doctors at Misrata’s main hospital said a ship left Misrata on Wednesday carrying dozens of wounded people to Benghazi, the rebels’ de facto capital in eastern Libya. One doctor said that there had been 65 injuries on Wednesday and 123 on Tuesday, and that at least one person had died. A rebel fighter told the Associated Press on Wednesday that five rebels had died.

Control of Misrata’s airport is important because it could be used to fly in humanitarian aid. It was unclear Wednesday how close Gadhafi’s forces remained to the airport and whether they could continue attacking.

As the rebels were consolidating their gains, U.N. Secretary General Ban Ki-moon called Wednesday for an immediate cease-fire in Libya, saying that he had spoken with Gadhafi’s prime minister and would be sending a special envoy to Tripoli “as soon as possible.”

But Jibril, of the opposition’s Transitional National Council, said rebels opposed a simple cease-fire. “A cease-fire without any political process is the actual and real partition of the country. This is not acceptable at all,” he said.

NATO said Wednesday that it welcomed the idea of a cease-fire, even though it has escalated its bombing campaign in recent days. Gadhafi also called for a cease-fire in his last public appearance on state television, 12 days ago. But neither side has stopped fighting.

Late Wednesday, Gadhafi met at a Tripoli hotel with tribal leaders from the eastern part of the country, senior government officials said. The meeting was shown on Libyan state TV and marked his first appearance in public since April 30, when NATO airstrikes hit his complex, apparently killing a son and three grandchildren.