KANO: At least 13 people were killed in the Nigerian city of Damaturu on Friday in three suicide attacks carried out by girls as residents prepared for the Eid festival at the end of Ramadan, police said. The attacks, in an area hard hit by the Boko Haram insurgency, came just days before Nigeria's new President Muhammadu Buhari travels to Washington for talks with his US counterpart Barack Obama. Buhari is expected to use Monday's meeting with Obama to push for US help to tackle the jihadist violence, which has surged since he took office in May. Boko Haram have increasingly used young women and girls as human bombs over the past year as part of campaign of terror, which has left 15,000 people dead and 1.5 million homeless since 2009. Residents said twin explosions near a prayer ground in Damaturu had killed two people, before a third blast went off moments later near a mosque leaving another 11 people dead, according to medics. "Thirteen people were killed in the... suicide blasts," said Markus Danladi, Yobe state police commissioner. "The attacks were carried out by three underage girls. Fifteen people were also injured in the attacks." The attacks followed a double bombing at a market in the town of Gombe, south of Damaturu, on Thursday evening that killed at least 49 people who were shopping for the Eid celebrations. This year's Ramadan has been particularly deadly, with suicide bombers hitting mosques and worshippers gunned down as they prayed. "There were two blasts near the Eid prayer ground," said Ahmad Adamu, a security volunteer in Damaturu said of Friday's attacks. "The first blast went off around 7:15 am (0615 GMT) while security volunteers who had come earlier than worshippers were waiting for the worshippers so they could assist in crowd control. Two were killed and three were injured," he said. "While we were attending to the victims we heard another blast about 500 metres (yards) away." Damaturu is the capital of Yobe, one of three northeastern states worst affected by the insurgency. 'Strengthen cooperation' Nigeria's new army chief Major General Tukur Buratai was due to visit Damaturu on Friday to celebrate Eid with soldiers battling the jihadists, who have pledged allegiance to the Islamic State group that has seized swathes of Iraq and Syria. Buhari, a former military head of state, has made the fight against Boko Haram one of the main planks of his administration -- but more than 700 people have been killed in attacks since he came to office. Topping the agenda of his talks with Obama "will be measures to strengthen and intensify bilateral and international cooperation against terrorism in Nigeria and west Africa", a statement from the Nigerian presidency said. Relations suffered in the latter part of former Nigerian president Goodluck Jonathan's rule, with Abuja considering US aid to fight Boko Haram insufficient. The west African nation decided to halt a US training programme for an army battalion which would have developed into a unit to take on the militants. The US State Department reacted by saying it would do what was needed to assist Nigeria. But it also expressed concern over respect for human rights and protection of civilians during military operations. The Islamist militants have taken advantage of the transitional period between Buhari's installation and the deployment of a regional force of 8,700 troops, scheduled for late July, to launch deadly attacks on an almost daily basis. The group has also carried out suicide bombings in neighbouring Chad and Cameroon. Washington, which has consistently condemned Boko Haram attacks, has said it can provide material aid to Nigerian forces and encourage countries in the region to combat the group. The United States already shares intelligence on Boko Haram with Nigeria, and last year sent military and civilian advisers to try find the more than 200 school girls abducted from their school in Chibok in the northeast. The girls are still missing.