The Prime Minister Dr. Manmohan has returned to Delhi after a two nation tour of the United States and Trinidad and Tobago. Talking to media on Board Special Aircraft, the Prime Minister described his tour as "very productive", and said that the US President is a friend of India.<br/> <br/>During his four-day State Visit to US, the first by any foreign leader under the 10-month old Obama Administration, Mr. Singh met President Barack Obama at the White House and held talks on the entire gamut of bilateral relations, the situation in the region and global challenges like terrorism, climate change and the economic crisis.