Two female suicide bombers carried out deadly attacks Monday in northern Nigeria, the latest violence to hit the city of Kano.
One woman blew herself up as she stood in line with other women who were waiting to buy kerosene for cooking, killing three people.
Hours later, a second bomber blew herself up in a commercial district of the city, injuring six people.
No one has claimed responsibility for the bombings. However, several attacks in the last week have been blamed on the Islamist group Boko Haram. The attacks have prompted Kano authorities to cancel festivities marking the major Muslim holiday of Eid al -Fitr.
Boko Haram is also suspected in a Saturday attack in the Cameroonian town of Kolofata in which a number of people were killed and others kidnapped, including the mayor and Muslim spiritual leader, Seini Boukar Lamine, his entire family and the wife of Deputy Prime Minister Ahmadou Ali.
A U.S. State Department spokeswoman Jen Psaki said Monday that the United States abhors the increasingly brazen attacks by Boko Haram, including the weekend attack in Cameroon.
"Our sympathies and thoughts are with the victims and families of this latest egregious assault on innocent civilians by a terrorist organization, Boko Haram, bent on fomenting violent extremism and insecurity in northeastern Nigeria and the region," said Psaki.
She said the United Sates has been working closely with Cameroon's government for some time as part of a coordinated regional response to Boko Haram.
In Nigeria on Sunday, five people were killed in an attack on a Catholic church in Kano. In a separate incident in Kano, a female suicide bomber was the only fatality in an attempt to kill police there.
Last week, at least one person was killed and eight others injured in a powerful explosion at a crowded bus depot in Kano.