Angry over lack of progress to resolve one of the highest-profile mass kidnappings in the world, Nigerians marched in their country's major cities on Thursday to demand the safe return of girls who were abducted by Boko Haram extremists two years ago from a school in Chibok.

Nigerian Vice President Yemi Osinbajo was expected in the northeastern town of Chibok for the anniversary of the kidnappings, said Yakubu Nkeki, leader of a support group of parents of the kidnapped girls. He said the community is angry that their only school remains in ruins. Boko Haram firebombed buildings as they took off with girls.

Some 20,000 children in the town and its surroundings have no school to attend, Nkeki said Thursday as parents gathered at the ruins of the school to pray for the safe return of their daughters.

"Boko Haram has achieved its aim. They say they don't want us to have Western education and our children don't," Nkeki said.

Two years ago, the Islamic extremists seized 276 girls who had gathered for science exams at the Government Girls Secondary School in the northeast town of Chibok. Some managed to escape, jumping off pickup trucks as the Islamic extremists drove them toward the Sambisa Forest. A total of 219 remain missing.

On Wednesday, CNN broadcast parts of a Boko Haram video of girls wearing the Islamic hijab, and CNN also aired its own images of tearful mothers, including one reaching out to a computer screen as she recognized her kidnapped daughter.

The video shows 15 of the girls — one with a mischievous grin, one looking uncompromising, downright defiant, and one downcast. One can feel the pain that shows in the eyes of many of them. They give the date of the video as Christmas, Dec. 25, 2015.

While Boko Haram is thought to have abducted thousands of people over the years, the mass abduction brought the extremist group to the world's attention. The campaign hashtag #BringBackOurGirls went as far as the White House, used by U.S. first lady Michelle Obama.

CNN reported that the video was sent in December to negotiators trying to free the girls. CNN's report included Information Minister Lai Mohammed saying the government is reviewing and assessing the video, which it apparently demanded as "proof of life" from Boko Haram.

Sen. Shehu Sani, who has been involved in past negotiations with Boko Haram about the Chibok girls, told The Associated Press he found the video credible. Nkeki, leader of the support group for parents of the Chibok girls, said he briefly saw part of the CNN video, in between power blackouts frequent in Nigeria, and "those are definitely our girls."

There's been no word from the Chibok girls since May 2014, when Boko Haram leader Abubakar Shekau said they had converted to Islam and threatened to sell them into slavery or forced marriage with his fighters.