A joint military operation in Afghanistan's Kunduz province said it killed a leader of the Islamic Movement of Uzbekistan.

The NATO-led International Security Assistance Force issued a statement Thursday announcing the death of Qari Yahya, an IMU leader, during an operation Tuesday in Qal-al-ye Zal district in Kunduz.

As the security force approached Yahya's location, he and another IMU leader reportedly moved from the compound and acted in a hostile manner toward Afghan and coalition troops. In the ensuing fight, Qari Yahya was killed and the other IMU leader was arrested.

Yahya is said to be responsible for facilitating and conducting improvised explosive device attacks throughout Kunduz, which is on the northern Afghanistan border near Tajikistan and Uzbekistan.

Yahya also maintained communication and logistic ties with senior IMU and Taliban leaders, ISAF said.

Yahya was "believed to have directed IMU insurgent activity for Kunduz province, including the financing, manning, and provision of weapons and equipment for attacks on Afghan and coalition forces," the ISAF said.

The IMU grew out of the "Adolat" -- Uzbek for "justice" -- Islamic movement. In 1998 the IMU started operating from a base in Tajikistan's Tavildara District. On Feb. 16, 1999, IMU activists set off six simultaneous car bombs in Tashkent in an attempt to assassinate the Uzbek President Islam Karimov. IMU members also participated in cross-border incidents from Kyrgyzstan's Batken province in 1999 and 2000.

Many IMU activists fled to Afghanistan and affiliated themselves with al-Qaida. The subsequent U.S. Operation Enduring Freedom against the Taliban and al-Qaida, which began in October 2001, saw the coalition's overwhelming aerial superiority decimate the IMU ranks. That allowed for a breathing spell for the Uzbek government in its ongoing battles with, not only the IMU, but other militants as well, which sought to establish an Islamic caliphate in place of the Karimov regime.

ISAF forces still face an uphill struggle. Recent U.N. internal reports on stability in Afghanistan have conceded that al-Qaida-linked groups like the IMU, fuelled by money from the narcotics trade, have extended their reach to northern Afghanistan. They pose threats not only to Afghanistan but also the country's Central Asian neighbors Uzbekistan, Tajikistan and Kyrgyzstan.

The IMU-linked Islamic Jihad Union, which includes recruits from Germany, Turkey, Tajikistan and Uzbekistan, also operates in Afghanistan.

Heroin, Afghanistan's most valuable crop, is a key financial resource for the Taliban and other insurgents. Three years ago the U.N. Office on Drugs and Crime estimated that the Taliban alone earns about $150 million a year from the opium trade, primarily by raising protection money from the country's key opium-producing syndicates.