The phone call from President Barack Obama to Narendra Modi to congratulate him on his electoral victory "set the tone" for ending the chill in the US' relations with the Indian leader caused by a decade-long visa ban, America's interim Ambassador Kathleen Stephens said today.

"I arrived here in June shortly after the new government was formed. You know that President (Barack) Obama called up Prime Minister elect even before he was sworn in to congratulate him and extend an invitation and I think that set the tone," Stephens, US Ambassador Charge d'Affaires ad interim to India told reporters.