"The US grieves with India on the loss of former Prime Minister #AtalBehariVajpayee," Juster said in a tweet.
"He will be remembered for his immense contribution to bolstering #USIndia relations and for recognizing us as 'natural allies'," he added.
"We extend our deepest condolences to the people of India."
Vajpayee, 93, passed away at AIIMS here soon after 5 p.m. on Thursday following a prolonged illness.