Washington

COUNTLESS threats stalk the Pakistani government, from militants in the tribal regions near Afghanistan to a backward economy teetering on collapse. In recent weeks, the focus has been on the Haqqani network, fundamentalist fighters along the border who have longstanding ties to Pakistani intelligence and have conducted deadly attacks on American troops and officials in Afghanistan.

Yet Pakistan also faces another, less publicized, challenge — from a banned Islamist organization that does not mount spectacular attacks but is nonetheless insidious. The group, Hizb-ut-Tahrir, is part of an international Islamist movement that promises to establish a caliphate through a bloodless revolution led by elite recruits.

Hizb-ut-Tahrir is not known to have committed a violent act in Pakistan. Instead, according to analysts, it looks for turncoats, proselytizing among officials in inner circles who have the power to bring the government down from within. If they succeed, Pakistan’s nuclear arsenal might fall into hands that are even less reliable than those of the military, which controls the country’s security.

The organization operates in more than 40 countries, including Britain and the United States, and has been active in Central Asia for more than a decade. But special concern arose in Pakistan after an army brigadier named Ali Khan was arrested in May 2011; his six-month trial, on charges of having ties to Hizb-ut-Tahrir, and of conspiring to overthrow the government, ended in June but a verdict has not yet been announced.