The first lady extended sympathy as a parent to the parents who lost children in the mass shooting last Friday, but also promised them that sympathy is not all their country would offer.

"I want you to know that this is just the beginning. 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," she wrote. "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."

President Obama visited Newtown the weekend after a gunman murdered 20 children at Sandy Hook Elementary School. He spoke at a prayer vigil and has since pressed Congress to introduce specific legislation addressing gun violence.

The first lady also on Friday posted advice to all parents on the White House website, offering "some ideas for discussing the tragedy in Newtown with children and young people."

"We can tell our kids that we’re doing everything we can to keep them safe and make sure they feel loved – and so are their teachers, coaches, faith leaders, Scout leaders and everyone else who plays a role in their lives," she wrote. 

She suggested teaching young people to be grateful for teachers, first responders, neighbors and parents by teaching them about "the extraordinary people of Newtown and how they have responded to unspeakable tragedy."

"Those are the values that give us our strength as Americans and that we return to in times of crisis – not just because they help us heal, but because they define who we are, as a people and as a nation," she wrote.