NATO boosted its bombardment of Libya Saturday, for the first time sending attack helicopters on low-altitude missions against military installations loyal to Libyan leader Moammar Gadhafi.

NATO said British Apache and French Tiger and Gazelle helicopters carried out the assaults. Military officials said about 20 targets were destroyed, including a radar site and an armed checkpoint, in the first deployment of the aircraft since British and French leaders approved their use in recent days. All three aircraft are equipped with missiles, such as the Hellfire missiles that skim low across the landscape toward targets that are pre-set by radar before the missiles are launched.

The commander of NATO's forces in Libya, Canadian Lieutenant General Charles Bouchard, said the successful assault “demonstrates the unique capabilities” of the attack helicopters. The use of lower-flying helicopters for attacks could diminish the possibility of civilian casualties, although they also could be vulnerable to strikes by surface-to-air missiles.

In recent days, rebels trying to oust Mr. Gadhafi have been waiting for use of the attack helicopters. One rebel leader in Misrata, Fatih Bashagha, said the fighters are happy about their use, and other rebels said it showed a renewed NATO commitment to assisting them.

The increase in the military campaign came even as new diplomatic efforts were seen in the effort to get Mr. Gadhafi to give up power.

China says its ambassador to Qatar has met with the head of Libya's rebel council, the first time China has revealed such contacts. Chinese officials said they stand by their position that the Libyan crisis should be resolved politically and that the country's future must be decided by its people.

Also, Russia is sending a special presidential representative, Mikhail Margelov, to Benghazi, to meet with the rebels. French Foreign Minister Alain Juppe said Friday that Mr. Gadhafi is “increasingly isolated.” Juppe also said that France is working with those close to the Libyan leader to persuade him to leave.

For the last several nights, NATO warplanes have bombed targets in Tripoli, including Mr. Gadhafi's sprawling residential and command compound. Mr. Gadhafi has rarely been seen in public since a NATO airstrike killed one of his sons in April.

On Friday, United Nations officials criticized Qatar's forcible deportation of a Libyan woman, Imad al-Obeidi, who says she was gang-raped by troops loyal to Mr. Gadhafi.