DURBAN, South Africa - Brazil, South Africa, India and China, known as "BASIC countries", remained united over major issues in relation to climate change, a senior Chinese official on climate change said here on Tuesday.

BASIC countries are united and demand that the second commitment of the Kyoto protocol "is a must," Xie Zhenhua, who led a Chinese delegation to the UN Climate Change Conference in Durban, South Africa, told a joint news briefing with his South African, Indian and Brazilian counterparts.

"The BASIC countries are united firmly..we are countries of action. We are ready to do our due contributions on climate change to advance the Durban conference a success," Xie said.

"We'll speak with the same voice" at the ongoing COP17, said Xie, who is vice chairman of the National Development and Reform Commission of China.

He refuted rumors that the BASIC countries had splitted due to their "differences" over the major issues being discussed at COP 17.

"Facts cannot be distorted and rumors will not be turned into facts," he said.

BASIC countries called on developed countries to "step up to fulfill" their pledges in fight against climate change.

They made the appeal  in the 17th Conference of Parties (COP17) to the United Nations Framework Conferences of Climate Change (UNFCCC).

"It is very important that, in Durban, a clear and ratifiable decision on Kyoto Protocol (KP) second commitment period takes place," Indian Environment and Forests Minister Jayanthi Natarajan said at the joint press briefing of the BASIC countries.

"This must happen if KP parties are really committed to addressing climate change. Developing countries should not be asked to make a payment every time an existing obligation becomes due on the part of developed countries. We have already walked the extra mile and in fact are doing more than what our parties are doing," said Natarajan.

"It is time that developed countries step up to fulfill their part of the commitment under UNFCC and Kyoto protocol," she noted.

As emerging economic giants, BASIC countries have been negotiating with each other to secure a second round of commitment from the rich countries under an extended Kyoto Protocol. Coming to an end next year, the 14 year old Kyoto Protocol is the only legal agreement on cutting greenhouse gases.

"India wants and is hopeful that the Green Climate Fund will be established at Durban. Developed countries parties who have commitment to provide resources should agree to capitalize the fund and also to the structure of long term sources of finance for the GCF," Natarajan said.

"The four countries that are presented on this table are committed. We are doing our part and we hope everybody will do the same. As BASIC we want to leave Durban with a fully functional Green Climate Fund, not just an empty shell," Brazil's climate negotiator Luiz Alberto Figueiredo told the media.

Basic countries are not a group and they are part of the Group 77 plus China, working together to safeguard the interests of developing countries as a whole, Xie said, stressing that BASIC countries are united as ever and are willing to take action to meet the challenge of climate change.

"We want to see the Durban climate talks to achieve substantial results," he said.

He reiterated that developed countries should bear for the historical responsibilities of climate change and lead the emission cuts while providing fund and technology to developing countries for better responding the climate change.

"Developed countries should carry out their commitment they have made in cutting emission and giving  financial assistance to help developing deal with climate change, he said.