First Lady Michelle Obama expressed her fury this week at the mass kidnapping of Nigerian schoolgirls by Islamist terrorist group Boko Haram. 

Michelle, speaking in place of President Obama in the weekly presidential address, said she and her husband are "outraged and heartbroken" over the abduction of more than 200 girls from their school on April 14, BBC News reported. 

Islamist militant group Boko Haram, which was declared a terrorist group by the West in 2013, claimed responsibility for the mass abduction. The group said the girls should not be in school but should "get married" instead. 

Michelle said the kidnapping reflects a worldwide crisis of girls being intimidated and threatened when they pursue an education.  

"What happened in Nigeria was not an isolated incident. It's a story we see every day as girls around the world risk their lives to pursue their ambitions," she said.

"Right now, more than 65 million girls worldwide are not in school, yet we know that girls who are educated make higher wages, lead healthier lives and have healthier families," she added.  

She also mentioned Pakistani girl and social activist Malala Yousafzai, who was shot and brutally wounded by the Taliban for speaking publicly in support of girls' education. 

"The courage and hope embodied by Malala and girls like her around the world should serve as a call to action," Michelle said.

It is the first time Michelle has delivered the weekly speech without her husband. 

Earlier in the week, she tweeted a picture of herself holding a sign that bears the message:  "#BringBackOurGirls".

The United Nations Security Council also expressed outrage over the kidnappings. The U.S. is planning to have U.N. sanctions imposed on Boko Haram. 

Both U.S. and British officials have traveled to Nigeria to try to rescue the girls. 

A senior Washington official also said the U.S. is considering a Nigerian request for surveillance aircraft to gather intelligence. 

Local officials in Borno state told the BBC that hunters armed with old-fashioned bows, arrows and shotguns will enter the forest where the girls are thought to be held hostage. According to the officials, 400-500 men have amassed but have not yet departed into the forest. They are still hoping that the local army will intervene. 

Nigeria is being blamed for not doing enough to find the girls, but Nigerian army spokesman Major General Chris Olukolade told the BBC that that is not true. 

"This is not the first time we're hearing of hunters wanting to go into the forest. The military has always carefully utilised the support and understanding of locals ... and others who have vital knowledge and information that could enhance counter terrorism operations," he said.

Boko Haram, which means "Western education is forbidden" in the Hausa language, began in Borno state in 2009. 

Around 1,200 people are estimated to have died in violence stemming from the terrorist group so far this year.