WASHINGTON - President Barack Obama will ask Congress for new authority to use force against Islamic State fighters next week, congressional aides said on Thursday.A House Democratic aide said lawmakers had been told they would receive the White House request next week.And an aide to Senator Bob Corker told Reuters the Republican chairman of the Senate Foreign Relations Committee expected Obama to send text of an authorization as soon as next week.Earlier on Thursday, US House of Representatives Speaker John Boehner said he expected Obama to seek congressional authorization for using military force against Islamic State soon and also called for speeding up assistance to Jordan.