Kano - Suspected Boko Haram attacks left more than 50 people dead on Wednesday, after Nigeria's president warned the United States that its policy was hitting the fight against Boko Haram.Twin suicide attacks in Maroua, northern Cameroon, killed at least 11, while some 42 lost their lives in a series of blasts at two bus stations in Gombe, northeast Nigeria.The latest atrocities came after Boko Haram released a new video on Twitter, maintaining they were not defeated and vowing: "We will be coming from where you never expected, stronger than before."A new, five-nation force - from Nigeria, Niger, Chad, Cameroon and Benin - is due to deploy by July 30 to take on the Islamic State Group-allied militants, whose six-year insurgency has left at least 15 000 dead and increasingly threatened regional security.Young girl bombersThe attack in Cameroon saw two girls aged "under 15" bomb the central market in Maroua, as well as the adjoining Hausa neighbourhood, said regional governor Midjiyawa Bakari.A source close to local authorities said "two girls, who were begging, blew themselves up" at about 03:00, causing "total panic" and leaving gruesome scenes of mutilated bodies and flesh, according to one journalist.President Paul Biya's office said 11 people were killed and 32 wounded, condemning the attacks against innocent civilians as "cowardly and despicable".Biya called on Cameroonians to be vigilant, with the attacks the second this month.On July 12, two female suicide bombers wearing the full Islamic veil blew themselves up in Fotokol, on the border with Nigeria, killing 10 civilians and a soldier from neighbouring Chad.Regional authorities have since banned the use of full-face veils.Bus station blastsIn Gombe city, blasts ripped through the Dadin Kowa bus station at about 19:30 and the Dukku terminus about 20 minutes later. Witnesses reported hearing two blasts at both sites.Lack of electricity in the area made it impossible to say whether they were suicide attacks or homemade bombs left at the scenes."So far we have recovered 12 dead bodies from the blast scene," said one rescue worker at the first site, who asked not to be identified. "The bodies are badly mutilated and we have several people injured."Gombe state police spokesperson Fwaje Attajiri confirmed the first blast but did not give a death toll.He had no details about the second explosion but one trader, whose shop is near the Dukku bus station, said: "There were two explosions. They happened after I had closed my shop for the day."I and others who were around came back and began pulling out bodies. I counted up to 30 dead bodies. I became sick and left."Last Thursday, 49 people were killed in a bomb attack on a market in Gombe city.Unwitting helpNigeria's President Muhammadu Buhari came to power on May 29 vowing to crush the insurgency but since then more than 750 people have been killed, according to an AFP count.Buhari, on his first trip to Washington as president, on Wednesday warned that a US refusal to arm his troops because of "so-called human rights violations" only helped Boko Haram.He had been hoping for greater military assistance on the trip but indicated he would come home empty-handed because of a US law that prohibits sending weapons to countries that fail to tackle rights abuses."Regrettably, the blanket application of the Leahy Law by the United States on the grounds of unproven allegations of human rights violations levelled against our forces has denied us access to appropriate strategic weapons to prosecute the war," he told an audience of policy makers, activists and academics.Nigerian forces had been left "largely impotent" in the face of Boko Haram's campaign of kidnapping and bombings, he added."They do not possess the appropriate weapons and technology which we could have had if the so-called human rights violations had not been an obstacle," he said."Unwittingly, and I dare say unintentionally, the application of the Leahy Law Amendment by the United States government has aided and abetted the Boko Haram terrorists."He appealed to both the White House and the US Congress to find a way around the law and to supply his troops with high-tech weapons under a deal "with minimal strings".