* Russia tells Libya contact group to respect U.N. authority
* China reiterates calls for immediate ceasefire
(Adds meeting with Medvedev, detail)
By Thomas Grove
MOSCOW, May 6 (Reuters) - Russia on Friday criticised a Western-led grouping that has pledged aid to the Libyan rebels fighting Muammar Gaddafi's forces, warning that it must not seek to usurp the authority of the U.N. Security Council.
Russian Foreign Minister Sergei Lavrov and his Chinese counterpart Yang Jiechi said the two nations -- both permanent Security Council members with veto power -- would work together to seek stability in the Middle East and North African region.
Russia and China, which abstained in the Security Council vote that authorised military intervention in Libya to protect civilians, have criticised the Western-led coalition conducting air strikes. Russia has accused it of overstepping its mandate.
After talks with Yang in Moscow, Lavrov criticised the Libya contact group of Western and Arab countries that agreed on Thursday to provide Libya's eastern rebels, based in Benghazi, with millions of dollars in non-military aid to help them keep services and the economy running. [nLDE74500B]
The contact group includes the other three veto-wielding permanent U.N. Security Council members -- the United States, Britain and France -- as well as Italy, Qatar, Kuwait and Jordan.
The contact group "is increasing its efforts to take on the leading role in determining the policy of the international community in relation to Libya," Lavrov told a news conference.
"We proceed from the position that the informal contact group comprises responsible states and that all of them ratified the U.N. Charter and are required to respect the authority of the Security Council."
Lavrov said the conflict in Libya was a civil war and the international community should focus on stopping the fighting and not "taking sides".
Russia and China "will coordinate our actions to foster the swiftest possible stabilisation" in the Arab world, he said.
Yang, who also met President Dmitry Medvedev, said the "sovereignty, independence and unity of Libya must be respected. People of all countries of the world ... have the right to choose their path of development."
He reiterated calls for an immediate ceasefire in order to prevent "a great humanitarian catastrophe in Libya".
Lavrov made clear that if asked, Moscow would not approve an international ground operation in Libya.
The Security Council resolution that authorised military intervention in Libya "directly and unequivocally rules out" ground operations, Lavrov said, when asked whether the council might authorise such intervention.
"The position of the Russian Federation remains absolutely unchanged," he said. (Reporting by Thomas Grove, writing by Steve Gutterman, editing by Janet Lawrence)