New Delhi, Jan 27 (IANS): A sense of relief spread like crisp mountain air among the security personnel in the national capital, snapping the tension and fatigue of the past several days as US President Barack Obama rounded up his three-day state visit to India Tuesday.

Obama and his wife Michelle reached the VVIP terminal of Indira Gandhi Airport around 1.45 p.m. in his official vehicle, The Beast, and took off at 1.55 p.m. in his Air Force One plane.

During his state visit Jan 25-27, Obama attended the Republic Day celebrations as the chief guest in the national capital and focused on improving relations between two of the worlds's largest democracies.

India's Research and Analysis Wing (RAW), Intelligence Bureau, Special Protection Group (SPG), National Security Guard (NSG) and paramilitary forces along with over 20,000 Delhi Police officers worked together to ensure Obama's safety by maintaining a tight vigil and a multi-layer security ring around him during his visit.

Special forces such as the quick response teams and fire service officials were also placed on high alert through the Obama visit.

"The capital city is already on high alert following terror threats. But, yes, there is a sense of relief now that the US president's visit is over," an official said.

Even the traffic police were out in full force as certain roads were blocked during his visit.

The Central Industrial Security Force, which was in charge of security arrangements in the airport area, had deployed additional contingents when Obama reached the VVIP Terminal area of the airport.

Union Minister Piyush Goel, Foreign Secretary Sujata Singh along with a few officials went to the airport to see him off.

Obama left for Saudi Arabia to offer his condolences to the Saudi royal family following the death of King Abdullah.