"One or even two swallows don't make a summer," reported Xinhua, citing Ryabkov in an interview published by the government's Rossiiskaya Gazeta daily.
There was no improvement in bilateral relations; on the contrary, negative trends continue to prevail near the end of the year, the diplomat said. These trends have been fed by the planned expansion of the Magnitsky List, which would inevitably incur Russian tit-for-tat response.
In April, the US released a list of 18 Russian officials suspected of human rights abuses under the so-called Magnitsky Act.
In a tit-for-tat response, Moscow published its own list of 18 US citizens who would be barred from entering Russia.
According to Ryabkov, the Magnitsky Act has become a long-term irritant in bilateral ties, and only Washington's political will could eradicate that source of tension.
Sergei Magnitsky, a lawyer for the Hermitage Capital Management investment fund, was arrested in November 2008 and died in a prison a year later, while under investigation of his alleged involvement in the fund's tax fraud.
The death of the lawyer triggered a legal chain reaction in Russia-US relations, with the US Congress adopting the so-called Magnitsky Act, which imposed visa bans and asset freeze on Russian officials allegedly responsible for the death.
Russia retaliated by the Anti-Magnitsky Act, banning US citizens to adopt Russian orphans and suspending a bilateral agreement on cooperation on children issues.