BAGHDAD (AP) — Islamic State militants disguised in Iraqi army uniforms and driving stolen Humvees killed at least 40 Iraqi soldiers and captured 68 others in western Anbar province, breaking through a deteriorating Iraqi military offensive in an area where the United States recently broadened its airstrike campaign.

The wave of suicide bombings dealt a heavy blow to government efforts to rein in the militants, whose rampage has seized much of the country’s north and west — even as the U.S. and its allies began training Iraq’s Kurdish peshmerga fighters to bolster their ability to battle the Sunni extremists.