U.S. and Iraqi forces have arrested more than 110 men since Operation River Gate kicked off in western Iraq on Oct. 4, officials said Thursday.

Six men the U.S. military called “al-Qaida in Iraq terrorists” have been killed in the fighting, mainly in the cities of Haditha, Haqlaniyah and Barwana.

The operation, called Bawwabatu Annaher in Arabic, is the latest in a series of offensives attempting to stem the flow of fighters and supplies entering Iraq from Syria. U.S. and Iraqi officials have long said Syria is not doing enough to stop the influx of foreign fighters across the vast western Iraqi deserts.

Haditha, in particular, has been a hotbed of insurgent action. Its hospital has been targeted by insurgent attacks, including at least one suicide car bomb earlier this year. During this operation, Iraqi soldiers are providing additional security for the hospital, officials said.

There are some 350 Iraqi soldiers involved in the operations, along with U.S. Marines, sailors and soldiers assigned to Regimental Combat Team 2. The Marines are responsible for a huge swath of land in western Iraq.

Operation River Gate kicked off with pre-dawn airstrikes on bridges in Dulab, Haditha and Barwana. In previous offensives, many insurgents fled those cities, which lie along the Euphrates River.

“The strikes were carefully executed to disable the bridges and limit the terrorists’ ability to flee the cities,” according to a Marine Corps release.

“Essential services such as electricity, water and access to medical care have not been disrupted by the ongoing operation.”

At least four U.S. servicemembers have been killed during the operation, officials said.

Farther west, a second operation — dubbed Iron Fist — has resulted in at least 42 suspected insurgents killed, officials have said.

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