(Reuters) - Russia will back an alternative Syrian opposition delegation to negotiate with Syria’s government at peace talks in Geneva later this month if the existing opposition team is not reformed or boycotts the talks, a Russian diplomat said on Thursday.

“What we are trying to achieve is to either expand the ‘Riyadh’ delegation to include the moderate opposition or to have a separate opposition delegation,” the diplomat said.

The U.N. Special Envoy for Syria Staffan de Mistura said on Wednesday the talks may be delayed, but major powers must keep up the pressure to bring participants to the table.

Kerry met de Mistura in Davos on Thursday and held talks with Russian Foreign Minister Sergei Lavrov on Wednesday at which they both said talks should go ahead in January despite the apparent lack of agreement on who should represent the opposition.

Friday Jan. 29 is “the last day” for convening the talks, the Russian diplomat said.

A Syrian opposition council backed by Saudi Arabia said on Wednesday it would not attend the negotiations in Geneva with the government if a third group took part.

But the Russian diplomat said that if the opposition council did not turn up in Geneva, the talks would still go ahead.

“(In case of a boycott), then the number two delegation comes. They will negotiate with the government,” the diplomat said.

“Either Kerry will convince the Saudis to expand (the opposition representation) or we will opt for a second delegation.”

The second delegation would include Saleh Muslim from the Kurdish PYD group and activists such as Haytham Manna, Qadri Jamil, and Randa Kassis.

A Western diplomat dismissed the Russian comments and said that without the opposition there would be no talks to speak of.

A delegation of civil society groups, and potentially a delegation representing Syrian women, might also take part in the Geneva talks, depending on how De Mistura decides to organize them, the Russian diplomat said.

The diplomat said the international powers convening the talks had not agreed which Syrian groups should be considered terrorist, and that discussion was likely to continue in parallel as De Mistura launches the peace talks.