WASHINGTON (AP) — Pushing back against her critics, Melania Trump said Tuesday she's committed to fighting cyberbullying despite the knocks she's gotten for taking on the issue when her husband regularly uses Twitter to berate his foes and call them names.

"I am well aware that people are skeptical of me discussing this topic," the first lady said. "I have been criticized for my commitment to tackling this issue, and I know that will continue. But it will not stop me from doing what I know is right. I am here with one goal: helping children and our next generation."

Mrs. Trump made her comments as she convened executives from major online and social media companies at the White House to discuss cyberbullying and internet safety. The meeting came more than a year after she announced that cyberbullying would be her cause if Trump were elected president.

The choice was immediately assailed, but Mrs. Trump said she won't back down.

She said she gets many letters from children who have been bullied or feel threatened on social media. She acknowledged that the issue has been studied for years, and told the executives she wants to hear "what you have learned, what has been accomplished, and what progress still needs to be made."

"I believe together we can make a real difference in encouraging positive behaviors on social media," she added.

Amazon, Snap, Facebook, Google, Twitter and Microsoft sent representatives, as did the Internet Association and the Family Online Safety Institute.

All the major technology companies have strict policies prohibiting harassment and other bullying behavior on their services, but primarily rely on users to report abuses and weed them out. They try to clearly spell out the kinds of remarks and other posts that won't be tolerated in special sections such as one Facebook, the largest online social network, has set up. Instagram, a popular service among kids and young adults for sharing photos and videos, provides links to the U.S. government's anti-bullying site and tips from a cyberbullying research center on one of its help pages.

But the efforts so far have fallen short, leading to rampant abuses that even some of the companies acknowledge have driven away or tormented portions of their audience.

It got so bad on Twitter, which has 68 million U.S. users, that the San Francisco company vowed last fall to crack down on hateful tweets. Among other things, Twitter adopted new policies aimed at protecting women who unknowingly or unwillingly had nude pictures of themselves distributed online — a common bullying tactic.

Yik Yak, another messaging app once popular among high school and college students, shut down last year partly because schools banned it following complaints about bullying and harassment.

Online bullying takes many shapes, but some of the most common tactics include posting embarrassing or salacious photos, making demeaning or cruel remarks under a photo or in a general post about someone, and sharing screenshots of what at least one person thought was a private text.

Harassment is widespread and extends beyond teenagers. A Pew Research Center poll last year found 41 percent of U.S. adults believed they had been harassed online.

The popularity and volume of content on major social media sites presents a huge challenge in policing what is being shared. Facebook, for instance, has 2.1 billion worldwide users who collectively share billions of posts on their pages daily. More than 300 hours of video is uploaded to Google's YouTube site every minute.

The companies are also constantly struggling to balance the desire to prevent harassment and other abuses with a commitment to freedom of expression.

In some cases, they see harassment and still look the other way. For instance, some of President Trump's more vitriolic tweets have openly mocked and denigrated people, prompting calls for Twitter to shut down his account and ban him from its service. But Twitter has declined, maintaining the news value of the president's tweets eclipses complaints about him being a bully.

There is no federal law that applies to bullying. State laws vary, ranging from requiring public schools to have bullying policies to requiring anonymous reporting systems, said Sameer Hinduja, co-director of the Cyberbullying Research Center and professor of criminology at Florida Atlantic University. The federal government can best help by giving schools more tools and money to provide programs, Hinduja said.

Mrs. Trump announced in a speech near the end of the 2016 presidential campaign that her priority as first lady would be to fight cyberbullying.

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AP Business Writer Michael Liedtke in San Francisco contributed to this report.

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