"There are more dead than injured," said Dr. Ahmed Radwan, an Egyptian who had been there helping for three weeks.
Jalaa's Dr. Gebreil Hewadi, a member of the rebel health committee, said city hospitals had received 27 bodies.
"Libya is not yours. Libya is for the Libyans. The Security Council resolution is invalid," he said in the letter to Sarkozy, British Prime Minister David Cameron, and U.N. Secretary-General Ban Ki-Moon.
To Obama, the Libyan leader was slightly more conciliatory: "If you had found them taking over American cities with armed force, tell me what you would do."
In a joint statement to Gadhafi late Friday, the United States, Britain and France — backed by unspecified Arab countries — called on Gadhafi to end his troops' advance toward Benghazi and pull them out of the cities of Misrata, Ajdabiya and Zawiya. It also called for the restoration of water, electricity and gas services in all areas. It said Libyans must be able to receive humanitarian aid or the "international community will make him suffer the consequences" with military action.
Foreign Minister Moussa Koussa said that Libyan officials had informed the U.N. and the Security Council that the government was abiding by the cease-fire it had announced Friday and called for a team of foreign observers to verify that.
"The nation is respecting all the commitments put on it by the international community," he said, leaving the podium before answering any questions about Benghazi.
In the course of the rebellion, Libya has gone from a once-promising economy with the largest proven oil reserves in Africa to a country in turmoil. The foreign workers that underpinned the oil industry have fled; production and exports have all but ground to a halt; and its currency is down 30 percent in just two weeks.
The oil minister, Shukri Ghanem, held a news conference calling on foreign oil companies to send back their workers. He said the government would honor all its contracts.
"We are still considering all our contracts and agreements with the oil companies valid," he said. "We hope from their part that they will honor their agreements, that they will send back their experts and their people to work."
He suggested future decisions on oil deals would favor countries that did not join the international force against Gadhafi: "A friend in need is a friend indeed," he told reporters in Tripoli.
Italy, which had been the main buyer for Libyan oil, offered the use of seven air and navy bases already housing U.S., NATO and Italian forces to enforce the no-fly zone over Libya.
Italy's defense minister, Ignazio La Russa, said Saturday that Italy wasn't just "renting out" its bases for others to use but was prepared to offer "moderate but determined" military support.
A French fighter jet fired Saturday on a Libyan military vehicle, the first reported offensive action in the international military operation against Gadhafi's forces, French Defense Ministry spokesman Thierry Burkhard said.
Warplanes from the United States, Canada, Denmark arrived at Italian air bases Saturday as part of an international military buildup. Germany backed the operation but isn't offering its own forces.
American ships and aircraft stationed in and around the Mediterranean Sea did not participate in the initial French air missions, but the U.S. prepared to a launch a missile attack on Libyan air defenses later Saturday, according to two U.S. officials familiar with the unfolding intervention. Both officials spoke on condition of because of the sensitivity of military operations.
British Prime Minister David Cameron said after the summit: "The time for action has come, it needs to be urgent."