Prime Minister Dr. Manmohan Singh is arriving back in New Delhi this afternoon, after concluding his successful visit to Washington for the Nuclear Security Summit and the IBSA and BRIC summits in Brasilia. <br/><br/>At the Nuclear Security Summit, the Prime Minister had voiced India's concerns on the threat of Nuclear arsenal finding its way into the hands of Terrorists and the need for measures to secure nuclear installations. <br/><br/>Dr. Singh stressed for preventing nuclear smuggling and to prevent proliferation. <br/><br/>47 nations that took part in the first historic Nuclear Sumit summit held at the initiative of US President Barack Obama, promised to be pro active in initiating individual action by countries and global co-operation to prevent a nuclear attack in the back drop of terrorist organisation like Al-Queda attempting to gain nuclear weapons. <br/><br/>In Brasilia, the Prime Minister's guidance led to the growing economic engagements among IBSA countries, comprising India, Brazil and south Africa. <br/><br/>The BRIC summit, comprising countries of Brazil, Russia, India and China, underlined the need for reforming the United Nations and International financial institutions to reflect current realities and to make them more representative. <br/>