MOSCOW — The Russian foreign minister, Sergey V. Lavrov, said on Monday that the government of President Bashar al-Assad of Syria was ready to engage in peace negotiations without preconditions and he urged the United States and other Western nations to bring Syrian opposition groups to the table for a new round of talks.

Mr. Lavrov, who met here on Monday with the Syrian deputy prime minister, Qadri Jamil, blamed opposition groups for the lack of progress in peace efforts. He and Mr. Jamil said that they had discussed the possibility of additional economic aid for Syria, in the form of a loan from Russia, with terms to be finalized later this year.

After more than two years of civil war, the Syrian economy is in tatters and the Assad government is heavily reliant on foreign aid, particularly from Russia and Iran. Russia is also an important supplier of arms and humanitarian aid to the Syrian government.

Mr. Lavrov and Mr. Jamil said that Russia would continue to sell weapons to Syria through existing arms contracts but said they had not discussed the sale of S-300 surface-to-air antiaircraft systems that have alarmed the United States and its allies, according to Russian news agencies.