US Vice President Joe Biden on Saturday promised a "new tone" in foreign policy under Barack Obama but warned other nations that improved relations were a two-way street. "I come to Europe on behalf of a new administration determined to set a new tone not only in Washington, but in America's relations around the world," he said in a major foreign policy address at the Munich Security Conference. He said that it was time to "reset the button" on Washington's frosty ties with Moscow, and that the US was willing to talk with the "great people" of Iran after three decades of frozen relations. But speaking on his first trip abroad since taking office along with President Obama on January 20, Biden said that US allies must also lift their game. "America will do more, but America will ask for more from our partners.