Islamic extremists carry out more violence in Nigeria

YOLA, Nigeria -- Islamic extremists blew up a bridge, killed an unknown number of people and abducted the wife and two children of a retired police officer in northeast Nigeria, residents said Saturday as an international effort got underway to rescue 276 schoolgirls kidnapped by the militants.

International outrage at the failure of Nigeria's military to rescue the girls abducted a month ago was joined Saturday by U.S. first lady Michelle Obama. In a radio address on the eve of the Sunday honoring mothers in the United States she said she and President Obama are "outraged and heartbroken" over the April 15 mass abduction.

"In these girls, Barack and I see our own daughters," Mrs. Obama said, referring to Malia, 15, and Sasha, 12. "We see their hopes, their dreams and we can only imagine the anguish their parents are feeling right now."

CBS News' Debora Patta reports from the capital of Abuja that rare anti-government sentiment in Nigeria is growing, and as the protests grow louder parents of the missing children are becoming angrier.

A well-known Nigerian Islamic scholar meanwhile warned that having foreign soldiers on Nigerian soil could escalate the conflict. Ahmed Mahmud-Gumi, speaking in northern Kaduna city on Friday, said it "may trigger waves of terrorism never seen before."

In the war zone, local government chairman Abawu James Watharda said no one could count the dead because 3,000 survivors have fled Friday night's attack on the town of Liman Kara.

Fleeing residents say the insurgents blew up the bridge that links the states of Adamawa and Borno that are under a military state of emergency to halt an Islamic uprising. That would cut off any military vehicles attempting a hot pursuit.

Militants Monday destroyed a bridge linking Nigeria to neighboring Chad, where it has hideouts in mountain caves.

There were no details about the latest children to be abducted. The Boko Haram terrorist network has said that its abductions of family members of Nigerian officials is a tit-for-tat measure since Nigeria's military and police often detain the spouses and children of wanted suspects.

Boko Haram has staged many attacks in northeastern Nigeria over the years, a campaign of bombings and massacres that has intensified in recent times despite a strong military presence there. Since May 2013 there has been a state of emergency in three northeastern Nigerian states wracked by Boko Haram violence.