The Interfax news agency quoted Russia's deputy foreign minister as saying consultations with Washington on a new treaty to limit the nuclear threat will begin in the next few weeks. Saturday's report quoted Sergei Rybakov as saying the talks should commence "before the end of April." The current Strategic Arms Reduction Treaty expires Dec. 5. Presidents Dmitry Medvedev and Barack Obama, during their first meeting in London earlier this week, set a nominal July deadline for the substitute treaty. That date would coincide with Obama's first presidential visit to Russia. Russia and the US hold the world's largest nuclear arsenals. The two leaders vowed to jointly pursue nuclear threats emanating from Iran, North Korea and al-Qaida terrorists in Pakistan.