"The young people in my country today, 100 years after the Italian fascist invasion, are today with their blood writing a new chapter in the history of struggle and resistance," Shaltut told the 47-nation council.
"We in the Libyan mission have categorically decided to serve as representatives of the Libyan people and their free will. We only represent the Libyan people," he said. "We will serve as their representative in this august body and international organizations."
The resignations come after the UN's top human rights official warned that mass killings in Libya, possibly of thousands, require the world to "step in vigorously" and immediately end a brutal crackdown on anti-government protesters in the North African country.
The UN high commissioner spoke with the most urgency yet by a UN official, citing estimates that thousands may have died at the hands of Gaddafi's security forces, possibly amounting to crimes against humanity.
"The crackdown in Libya of peaceful demonstrations is escalating alarmingly with reported mass killings, arbitrary arrests, detention and torture of protesters," Navi Pillay said during the council's daylong emergency meeting. "Tanks, helicopters and military aircraft have reportedly been used indiscriminately to attack the protesters. According to some sources, thousands may have been killed or injured."
Diplomats debated whether to call for Libya's ouster from the council, in what would be an unprecedented suspension of one of its own members. It will also decide whether to heed Pillay's call for an independent UN-led probe of abuses in Libya.
It was only last May that the former US enemy, Libya, was elected to the Geneva-based body as part of a series of attempts at political rehabilitation on the world stage.
UN Secretary-General Ban Ki-moon also was to meet with the powerful UN Security Council later Friday in New York to consider possible sanctions against Libya.
European nations were leading the effort to condemn Gaddafi's regime that has ruled for 42 years but now appears to have lost control of large parts of the country.
"The world is watching you, the world will hold you to account," British Prime Minister David Cameron told reporters Friday, referring to Gaddafi's regime. "International justice has a long reach and a long memory."
Russian President Dmitry Medvedev said in a statement on Friday that Libya must not be allowed any "further exacerbation of the situation, the destruction of the civilian population." It is the Kremlin's strongest criticism yet of Libya.
It is the first time that the Geneva-based council has held a special session to scrutinize one of its members. Libya's ambassador did not attend, but some of its allies spoke out against sudden measures to punish Gaddafi.In Brussels, NATO was holding an emergency meeting Friday to consider the deteriorating situation in Libya. It had received no requests to intervene and said it would only do so if it were given a United Nations mandate.
The UN Security Council also planned to meet later Friday in New York to consider actions against Gadhafi's regime.
French Foreign Minister Michele Alliot-Marie said France and Britain would press the Security Council for a "total embargo on weapons as well as sanctions, and also the referral of a case to the International Criminal Court for crimes against humanity."