The mother of a black Florida teen killed by a white neighborhood watchman endorsed Hillary Clinton for president Monday, praising the former secretary of state for her stance on gun control and ability to "stand up to inaction from Republicans and indifference from the NRA." Clinton reportedly won the support of Sybrina Fulton, mother of the late Trayvon Martin, during a meeting with mothers of children who died in shootings or at the hands of law enforcement in a November 2015 meeting in Chicago.

The endorsement comes as Clinton is fending off Vermont Sen. Bernie Sanders, who is surging in the polls in Iowa and New Hampshire. Clinton has been critical of Sanders' gun control record. He has voted to give gun makers immunity and against the Brady Handgun Violence Prevention Act five times.

"With so many of our children's lives on the line or taken, we simply can't afford to elect a Republican who refuses to even acknowledge the problem of senseless gun violence. The rising generation of our young people need a president who will stand up to inaction from Republicans and indifference from the NRA," Fulton writes in a CNN Opinion piece about the endorsement. "I believe that person is Hillary Clinton."

Martin was just 17 when he  was killed by George Zimmerman as he walked home, unarmed, in a small Florida town in February 2012, setting off a national debate on race and gun laws. Zimmerman was acquitted in July 2013.

Fulton's full endorsement is below:

"Today, throughout many communities of color, our young people go about their lives feeling as if they are a target in their country. It's become a sad fact of life that senseless gun violence can strike with little or no warning, either from neighborhoods that have become flooded with firearms, or police who are too quick to resort to deadly force.

Gun violence is an epidemic that kills 33,000 men, women, boys and girls every year. On top of those needless deaths, law enforcement agencies in America kill more people in a month than many other countries' police forces kill in years. When those precious lives are taken, it forever tears apart the lives of thousands more -- the friends and families who loved them, and who always will.

Losing a child is any parent's worst fear. As a mother who has had to live that horrible nightmare in a very public spotlight, I hope that by speaking out, it will help focus some of that light onto a path that can help our nation find its way out of this darkness.

Last week, President Barack Obama took some important steps that included strengthening the background check system for purchasing guns without diminishing our Second Amendment rights. I was glad to see these actions put in place, and was moved by the tears of not just our President but of a father who clearly understands my anguish.

But next year we will have a new president. And everything Obama has done -- even common-sense reforms that a majority of gun owners agree with -- will be overturned if that president is a Republican. In fact, the Republican candidates have vowed to roll back all of these sensible measures. And many of them have shown open contempt for the simple notion that Black Lives Matter.

With so many of our children's lives on the line or taken, we simply can't afford to elect a Republican who refuses even to acknowledge the problem of senseless gun violence. The rising generation of our young people need a president who will stand up to inaction from Republicans and indifference from the National Rifle Association.

I believe that person is Hillary Clinton.

I know Clinton is tough enough to wage this fight. I've seen her do it for years. As first lady, she advocated for the Brady Bill and convened meetings on school violence. As a senator, she voted to extend the assault weapons ban and against an immunity law that protects irresponsible gun makers and dealers from liability.

In spending some time with her in person, I also found a mother and a grandmother who truly heard me, and understood the depth of my loss.

She knew all the statistics. But like so many, I've long since grown numb to the numbers. So instead, we talked about Trayvon and other families who have lost a loved one to gun violence. We talked about all of the wishes and hopes we had for their lives. And knowing we can never get them back, we discussed how to prevent more moms from losing their sons to gun violence.

Clinton will uphold President Obama's recent executive actions, and then she'll go even further. Her plan focuses on reforms that would help keep more guns out of the hands of criminals. It would finally close the gun show loophole, and the outrageous provision that allowed someone with an arrest record to buy the gun used to shoot and kill nine parishioners at the Emanuel AME Church in Charleston, South Carolina.

I agree with the President: We should only support leaders that fight for common-sense gun reforms. Clinton passes that test.

Just as importantly, Clinton also wants to address the larger, systemic problems. She has a plan to begin to heal the distrust and divide that too often exists between law enforcement and the communities they serve.

She has called for key reforms -- from better training for officers to eliminating racial profiling and investing in body cameras for every police department. She sees what I see: a criminal justice system that is not always just. A system that has contributed to creating a reality where just selling cigarettes, playing loud music, looking at a cop the wrong way or walking home from the store are now activities that can get you killed.

If you look at the numbers, America is missing 1.5 million men of color -- lost to a system of violence and mass incarceration that seems to have long since forgotten them, but we haven't.

Not only am I missing my son, but too many other moms like me are missing their sons -- Eric Garner, Jordan Davis, Laquan McDonald, Freddie Gray, Michael Brown, Oscar Grant, Sean Bell, Tamir Rice. As their mothers, we must do more than just cry. And all of us must do more than speak out, protest and march.

We must vote!"