St Petersburg (Russia), May 30: As Prime Minister Atal Bihari Vajpayee arrived here today for some high-voltage diplomacy and interaction with the world's most powerful leaders, India indicated that it was in no mood to question the US on the emerging situation in Iran where Washington has even talked of a regime change. "No. No. We should be very careful. We have no reasons to get involved in discussions with interlocutors which in any way questions the policy of another big power," Foreign Secretary Kanwal Sibal told reporters on board the Prime Minsiter's special aircraft from Munich after his two-day visit to Germany. Sibal was asked whether during Vajpayee's meetings with leaders of Russia, France, Germany and China, who have opposed US' unilateral action in Iraq, India would campaign against the latest US moves in Iran. Vajpayee, during his stay here and in Evian in France which hosts the G-8 summit, would hold talks with leaders of China, France, Germany, Russia, Britain and other key nations. Vajpayee is one of Russian President Vladimir Putin's 43 special invitees gathered for the tercentenary celebrations of the city founded by Peter the Great, which had defeated Hitler's Nazi troops in World War II. It is also Putin's hometown. Bureau Report