(Adds British comment, detail on Russia's offer)
* Putin demands no countries excluded from new pact
* Powerful Russia PM points finger at U.S., Japan
* Tough line comes ahead of Sept. 22 U.N. talks
* Asks why should Russia be restrained, but not China
By Janet McBride
NOVO-OGARYOVO, Russia, Sept 11 (Reuters) - Prime Minister Vladimir Putin said on Friday he would reject any new climate change pact that imposed restrictions on Russia but not bind other big polluters, like the United States or China.
Putin's tough message indicates the difficulties that negotiators from nearly 200 countries face in ironing out the details of a complex new pact to combat global warming before a December deadline.
The drive to agree a new U.N. climate deal in Copenhagen by the end of this year is already considered under threat by some nations, with world leaders seeking to revive the bogged-down negotiations at a U.N. summit in New York on Sept. 22.
"We ratified the Kyoto protocol even though some colleagues tried to persuade us it was harmful to Russia's economy," Putin said.
"Other countries did not approve it and they are much greater polluters -- the United States," Putin told the Valdai group of academics and journalists at his Novo-Ogaryovo residence outside Moscow.
After a sharp drop in emissions when the Soviet Union fell in 1991, Russia's industrial revival has preserved its place as the world's third largest polluter behind China and the United States.
Russia has offered to cut its greenhouse gas emissons by 10-15 percent below 1990 levels by 2020, but its emissions were already 34 percent below 1990 levels in 2007, the latest year data were available.
"Russia's current (2020 emissions limit) offer is not a serious offer," said a British government source.
Putin said the climate problem could only be solved on a global scale where all countries shared the burden.
"The United States and China are leading economies and leading polluters. Should we restrain our development because of them? We won't agree with an approach that allows the exclusion of some countries."
Green groups and developing countries want industrialised nations to trim their emissions by 25-40 percent below 1990 levels, referring to a range of cuts suggested by a U.N. panel of climate scientists.
Small island states such as Tuvalu or the Maldives fear rising sea levels could wipe them off the map if tougher measures are not adopted to halt temperature growth that is leading to higher sea levels.
Both China and the European Union have complained that the pace of the talks has been too slow with no side yet prepared to concede ground on issues considered to be of vital economic importance. (Additional reporting by Gerard Wynn; writing by Conor Sweeney; editing by Peter Millership)