"We are all stunned, shocked, and distraught by this tragic shooting, by this violent act, and by the loss of so many young children. Our hearts go out to the families and friends of the students, teachers, and educators killed and wounded in Newtown, Connecticut," said House Minority Leader, Nancy Pelosi.
"The entire nation will continue to stand as a source of support to this community in the days and weeks to come," Pelosi said.
US Senator Mark Begich said he was deeply saddened by the "deplorable" act of violence against children, who are the most vulnerable of individuals.
House Democratic Whip Steny Hoyer described the incident as a parent's worst nightmare and called it a "senseless tragedy".
"There can be no consolation other than to know that they have the heartfelt prayers and support of an entire nation," Hoyer said.
Photograph: U.S. President Barack Obama wipes a tear as he speaks about the shooting at Sandy Hook Elementary School in Newtown, Connecticut
Credit: Larry Downing/Reuters
No lull and dip in Indo-US relationship: Nancy Powell
Housing prices to go up after land bill approval
Susan Rice withdraws from race of US Secretary of State
An Indian American ball for President Obama
Obama recognises Syria's opposition group