text: Up to a dozen A-29 Super Tucano aircraft would be sold to Nigeria to help fight Islamist militant group Boko Haram, unnamed US officials said.
  The deal, which is not yet official, will require approval from Congress.
  Boko Haram's deadly insurgency has displaced more than two million people.
  The deal, said to be worth up to $600m (Â£490m), was agreed by the Obama administration, but was reportedly halted on the day it was due to be sent to Congress, after a catastrophic incident involving the Nigerian military.
  About 90 people, mainly women and children, were killed in January when the Nigerian Air Force mistakenly bombed a camp in the country's north-east, which was hosting thousands of those who had fled Boko Haram.
  An aid distribution was taking place at the time of the attack, according to medical charity MSF.
  The Nigerian government indicated last month that the deal might be back on, following the first phone call between President Muhammadu Buhari and President Donald Trump.
  "President Trump assured the Nigerian president of US readiness to cut a new deal in helping Nigeria in terms of military weapons to combat terrorism," Mr Buhari's office said in a statement.
  The US congressional source said human rights concerns remain, despite support for the sale from some lawmakers, Reuters news agency reports.
  The US Air Force described the A-29 aircraft as a "game-changer" when they were deployed in Afghanistan in 2016.
  They can be armed with two wing-mounted machine guns and can carry up to 1,550 kg of weapons.
  But the aircraft that would be sold to Nigeria come with a "very basic armed configuration," one of the unnamed US officials told Reuters.
target: The Trump administration plans to sell military planes to Nigeria despite concerns over rights abuses and a botched air strike that killed scores of civilians in January, US media say.