Michelle Obama dropped by a roundtable of experts focused on international education Thursday morning and used the occasion to speak out again about the Nigerian schoolgirls kidnapped by the terrorist group Boko Haram. Seated in the center of a conference table with 14 people that her office described as international education experts,  the first lady said that “what has been going on in Nigeria is a tragic reminder” of the need for educating women and girls.

“Now that we have a bit of the world’s attention on this issue, we have to seize upon this moment and take the opportunity to really push to make some significant changes. Right now today, there are millions and millions of girls around the world who are not in school,” Obama said. “And it’s not because they don’t want to be in school. It’s because they don’t have the opportunity.”

It was the third time the first lady has brought up the capture of the Nigerian girls, who were taken from a boarding school last month. The U.S. government recently deployed 80 troops to neighboring Chad to help find the kidnapped children. The first lady sent out a tweet two weeks ago, with a photo of herself holding up a sign that read “#BringBackOurGirls,” indicating her solidarity with others calling for the rescue of the girls. Obama’s message has been retweeted more than 58,000 times. On May 10 she made it the topic of the president’s weekly radio address, which she gave for the first time.

Obama’s embrace of the issue comes as she has become a more forceful advocate for advanced education, and it marks a cautious move by the first lady into international causes.

As she closed her remarks, Obama said the issue of educating women and girls internationally is important to her and she plans to work on it long after leaving the White House

A woman seated to the first lady’s right remarked: “We don’t doubt that we’re going to be hearing from you.”

The room erupted in gentle laughter.