WASHINGTON — President Barack Obama says his administration has received an outpouring of support for stricter gun laws following last week’s elementary school massacre in Connecticut, telling respondents to an online petition: “We hear you.”

The president said in a video released Friday that he has been encouraged that many gun owners have said there are steps the nation can take to prevent more deadly shootings, “steps that both protect our rights and protect our kids.”

“I will do everything in my power as president to advance these efforts because if there’s even one thing we can do as a country to protect our children, we have a responsibility to try,” Obama said.

Obama was holding a moment of silence on Friday morning at the White House marking one week since the shooting that killed 20 children and six adults at a Newtown, Conn., elementary school. The National Rifle Association, the country’s foremost gun lobby, was holding a news conference on Friday in the aftermath of the shootings.

The president has challenged the NRA to “do some self-reflection” and join a broad effort to reduce gun violence. The organization said Tuesday it would offer “meaningful contributions to help make sure this never happens again.”

Gun-control measures have faced strong opposition in Congress for the past decade but Obama has suggested he intends to make it a key part of his agenda next year. In the video, he urged the public to become involved in

“If we’re going to succeed, it’s going to take a sustained effort of mothers and fathers, daughters and sons, law enforcement and responsible gun owners, organizing, speaking up, calling their members of Congress as many times as it takes, standing up and saying ‘enough’ on behalf of all our kids,” Obama said.

Meanwhile, in¬†a letter addressed to the people of Newtown,¬†Michelle Obama said she was “so proud of the outpouring of love and support that has come from every corner of America” in the wake of the tragedy.

Writing in the Hartford Courant newspaper, she added: “As a mother of two young daughters, my heart aches for you and your families. Like so many Americans, I wish there were something – anything – I could do or say to ease your anguish.

“As my husband has said, in the coming weeks, he will use all the powers of his office to engage citizens from across this country to find ways to prevent tragedies like this one. And please know that every minute of every day, we are thinking of you, and praying for you, and holding you and your families in our hearts as you begin the slow and wrenching work of healing and moving forward.”

The Associated Press and Reuters contributed to this report.