WASHINGTON - Top Pakistani military officials are increasingly concerned that their ranks are penetrated by Islamists who are aiding militants in a campaign against the state,The Washington Post reported Saturday. Citing a senior intelligence official, the newspaper said that Pakistan Army chief, Gen. Ashfaq Kayani, who like the civilian government has publicly expressed anger over the secret Abbottabad operation, was so shaken by the discovery of Osama bin Laden that he told U.S. officials in a recent meeting that his first priority was bringing our house in order. We are under attack, and the attackers are getting highly confidential information about their targets, said the unnamed official, citing his personal conversation with Gen. Kayani. In a dispatch from Islamabad, the Post said Pakistans top military brass purged the ranks of Islamists shortly after the Sept. 11, 2001, attacks. Since then, it pointed out, the nations top officials have made repeated public assurances that the armed forces are committed to the fight against extremists and that Pakistans extensive nuclear arsenal is in safe hands. "But U.S. officials have remained unconvinced, and they have repeatedly pressed for a more rigorous campaign by Pakistan to remove elements of the military and intelligence services that are believed to cooperate with militant groups," the dispatch said. "It is unclear how authentically committed Kayani and other top military leaders are to cleansing their ranks," it said. "But Kayani is under profound pressure, both from a domestic population fed up with the constant insurgent attacks and from critics in the U.S. government, who view the bin Laden hideout as the strongest evidence yet that Pakistan is playing a double game." I think he was in protective custody, one former U.S. official was quoted as saying about bin Laden. Pakistan has strenuously denied that. But military officials acknowledge that members of the services have cooperated with militants, the Post said. One senior military official said military courts have in recent years convicted several soldiers for roles in attacks on security installations convictions that have not been made public. Four naval officers previously arrested on suspicion of links to militants were questioned this week in connection with the assault on the naval base in Karachi, another security official said. The senior military official said belief in militant jihad long glorified in the national education curriculum is prevalent in the rank and file, making screening for it a daunting task that the military has been loath to perform.