U.S. Secretary of State John Kerry has held talks in Berlin with Chancellor Angela Merkel, senior German officials, and Russian Foreign Minister Sergei Lavrov.
The discussions focused on the Syria crisis and Iran's nuclear program.
After meeting German Foreign Minister Guido Westerwelle, Kerry said the international community's proposals to Iran include "reciprocal measures that encourage Iran to make concrete steps" toward addressing concerns about its nuclear research.
The five-hour meeting with Lavrov in Berlin -- Kerry's first as secretary of state -- comes at a time of heightened tensions between Washington and Moscow. The two spent half of their time discussing Syria.
The Kremlin has blocked efforts in the United Nations to take further action against Syria and banned U.S. adoptions of Russian children amid criticism from Washington about Russia's human rights record.
Speaking to reporters following the meeting, Lavrov urged the Syrian opposition to enter a dialogue with President Bashar al-Assad's government.
The comments come two days before a conference in Rome, where representatives of nearly a dozen countries meet with the Syrian opposition to explore ways to end the Syrian civil war.
The Syrian National Coalition has said it will attend the February 28 conference to drum up support for the opposition, reversing an earlier decision to boycott the gathering to protest "the world's silence" over the violence in the country.
Based on reporting by Reuters, AP, AFP, and dpa