The United States Tuesday condemned last week's "horrific and indiscriminate attacks" in northeastern Nigeria carried out by the Islamist militant group Boko Haram.
The October 23 and 24 bombings occurred at the newly built Jambutu Mosque in Yola, the capital of Adamawa state, and a neighborhood mosque in Maiduguri in Borno state, as well as other locations in that city.
The attacks left 61 people dead.
"We offer our deepest sympathies and condolences to the families and loved ones of the many innocent civilians who were killed and injured," U.S. State Department spokesman John Kirby said Tuesday.
Witnesses to the Yola blast said it happened as worshippers were getting ready for Friday afternoon prayers. Nigerian newspapers released photos showing flames and black smoke rising from the site of the blast.
Since mid-July, 292 people have been killed by suspected Boko Haram suicide attacks in Maiduguri and nearby communities, while 72 died in Adamawa state.
Many of the attackers used in those incidents were women and children.
"The apparent use of children - particularly young girls - to commit these attacks is especially heinous, and it provides yet more examples of the horrific measures Boko Haram is willing to take to terrorize civilians in northeast Nigeria and the Lake Chad Basin region," Kirby said.
The group has targeted both Christians and Muslims who do not adhere to its ideology.
(Hausa stringer Ibrahim Abdul-Aziz contributed to this report from Yola.)