The United States on Monday roundly condemned Boko Haram's "horrific and indiscriminate" attack targeting civilians in Chad, as well as recent assaults elsewhere in Africa by the radical militants.

Four people died in a suicide blast in the restive city of Maiduguri, while at least 11 people were killed when two women blew themselves up in the border town of Fotokol in northern Cameroon, attacks that once again underlined the regional threat posed by the Islamists.

Both came after a male suicide bomber, dressed as a woman and wearing a full-face veil, blew himself up at a crowded market in Chad's capital N'Djamena on Saturday, killing 15.

"The United States strongly condemns the horrific and indiscriminate Boko Haram suicide attack on the Grand Marche in the Chadian capital... as well as attacks in Cameroon, Niger and Nigeria over the past two days," State Department spokesman John Kirby said.

"Boko Haram's targeting of men, women and children highlights that the group's brutality and barbarism know no bounds, and we remain committed to working closely with the region to root out the threat posed by the group."

The statement added that US officials, already providing security and counterterrorism assistance programs, would step up its support to countries trying to combat the group.

"We look forward to expanding this support both bilaterally with the individual countries and to the Multinational Joint Task Force, which the Lake Chad Basin countries and Benin are in the process of standing up to coordinate their counter-Boko Haram campaign," Kirby said.

Ban condemns Cameroon suicide bombings
United Nations, United States (AFP) July 13, 2015 - UN chief Ban Ki-moon condemned twin suicide bombings in Cameroon -- the first by Boko Haram in the country -- and called for better cooperation to fight the militants.

At least 11 people were killed when two women blew themselves up in the border town of Fotokol in northern Cameroon.

Ban "strongly condemns the twin suicide bombings," his spokesman said.

He "encourages them to further strengthen their cooperation in addressing the threat posed by Boko Haram, as well as ensuring strict compliance with international humanitarian and human rights law," the statement added.

Ban said he was "encouraged" by measures already taken by Cameroon to fight against the militants and welcomed its efforts to host refugees fleeing the crisis.