The decision to engage primarily Afghan forces was taken by the Soviets, but was resented by the PDPA, who viewed the departure of their protectors without enthusiasm. In May 1987 a DRA force attacked well-entrenched mujahideen positions in the Arghandab District, but the mujahideen held their ground, and the attackers suffered heavy casualties. In the spring of 1986, an offensive into Paktia Province briefly occupied the mujahideen base at Zhawar only at the cost of heavy losses. Meanwhile, the mujahideen benefited from expanded foreign military support from the United States, Saudi Arabia, Pakistan and other Muslim nations. The US tended to favor the Afghan resistance forces led by Ahmed Shah Massoud, and US support for Massoud's forces increased considerably during the Reagan administration in what US military and intelligence forces called "Operation Cyclone". Primary advocates for supporting Massoud included two Heritage Foundation foreign policy analysts, Michael Johns and James A. Phillips, both of whom championed Massoud as the Afghan resistance leader most worthy of US support under the Reagan Doctrine.