On October 1 President George W. Bush signed the Iran Freedom Support Act, stipulating sanctions against countries that maintain energy cooperation with Iran and supply weapons to the country.
Sergei Lavrov, on returning from a visit to Poland, said: "The U.S. unilateral law on sanctions has complicated the collective work of the Iran-6."
The six powers mediating the Iran nuclear issue, the five permanent UN Security Council members plus Germany, have been trying to persuade Iran to accept a package of incentives, and suspend uranium enrichment, which many countries believe is the beginning of an Iranian nuclear weapons program.
Russia has consistently defended Iran's right to nuclear energy, and is building a nuclear power plant in the country under a $1 billion contract signed in 1995.
The United States has pressed for sanctions against Iran, but Russia and China, which hold veto-wielding authority at the UN Security Council, have resisted the idea.
The Russian minister said, "We agreed to do everything together, including analyzing of the situation, and formulating measures to influence [Iran]. But what has happened has happened. Let us see what we can do in this situation."
Lavrov said earlier on Thursday in Warsaw that the new U.S. law only made it more difficult for the international community to agree a collective approach to Iran's problem.
Negotiations between Iran-6 have stalled over Iran's failure to meet the UN Security Council's August 31 deadline for suspending its nuclear activities.
Lavrov, who has defended the Islamic Republic's right to pursue atomic research, said Russia was worried about the lack of a consistent reply from Tehran on the nuclear program issue.
"We are concerned that Tehran has provided no satisfactory answer on its nuclear program," he said.
Iran's President Mahmoud Ahmadinejad said Thursday that no sanctions would stop Iran from enriching uranium, a necessary step to creating a nuclear fission bomb.
In mid-September, negotiations between the European Union foreign policy chief, Javier Solana, and Tehran's chief nuclear negotiator Ali Larijani brought no progress in the dispute.
On Friday, the Iran-6 may meet in London to discuss the crisis, but the British Foreign Office has yet to confirm this.
Lavrov said the upcoming meeting in London would be guided by agreements reached within the group of six mediators. "But we will also look for additional opportunities to continue multilateral diplomatic efforts," Lavrov said.
The Russian minister, however, warned that additional pressure could be put on Iran.
"We concede the possibility of additional pressure on Iran, but this pressure must be aimed at beginning negotiations and achieving agreements that can ensure non-proliferation," he said.
