THE U.S. military has defended its air strikes against Taliban fighters as the insurgent group accused Washington of violating their signed agreement and warned of consequences if such actions continued. The Taliban launched a major offensive in the southern province of Helmand in a bid to take the provincial capital, prompting U.S. air strikes in support of Afghan security forces, which were being overrun. "American forces have violated the Doha agreement in various forms by carrying out excessive air strikes following the new developments in Helmand province," Taliban spokesman Qari Muhammad Yousuf Ahmadi said in a statement on Sunday. The…