Novak Djokovic and Rafael Nadal could headline next year's Kremlin Cup in Moscow, the Russian Tennis Federation president told R-Sport Thursday.

Former world No. 1 Yevgeny Kafelnikov, who is close to the Kremlin Cup organizers, said Wednesday that the two had been offered seven-figure sums to play the 2013 competition.

This year's edition of the ATP 250 tournament ended Sunday and featured a weak men's field headed by world No. 21 Alexander Dolgopolov.

"We're interested in Djokovic and Nadal coming, that possibility could happen, in principle," Tarpishchev said, adding that it could be confirmed as early as mid-January.

Budget constraints limit organizers' ambition, Tarpishchev said.

“Will it be possible to invite not only Nadal and Djokovic, but also Roger Federer and Andy Murray?” he said.

“This is big money, we can’t afford it.”

In May, Tarpishchev said that Federer, Nadal and Russian women's No. 1 Maria Sharapova were all in talks to play the 2012 tournament, but none played.

The Kremlin Cup started as a men’s event in 1990, and absorbed the former Moscow Ladies' Open in 1996.

This year’s tournament was held on hard courts at Moscow’s Olimpiisky arena, with the men’s event won by Italy’s Andreas Seppi and the women’s by Caroline Wozniacki of Denmark.