Officials say the rising violence indicates smugglers are frustrated and more desperate as it has become more difficult to cross the border illegally. Agents have been attacked with rocks, vehicles and Molotov cocktails.

"Criminals are discovering they can no longer operate with impunity in certain areas and are systematically being prevented from using the border for their criminal activities," Border Patrol Chief David Aguilar said in a news release.

The agency's San Diego sector, which encompasses western California, reported the steepest increase. Assaults more than quadrupled to 110 from Oct. 1 through Sunday, up from 24 in the same period last year.

The agency recently equipped agents in California and Arizona with a powerful, pepper-spray launcher that has a range of more than 200 feet. It has also fired tear gas into Tijuana, Mexico, several times in response to attacks.

Overall, the Border Patrol said agents were attacked 987 times during the 12-month period that ended Sept. 30, the highest since it began keeping track in the late 1990s.

By the end of 2008, The Department of Homeland Security plans to complete 370 miles of pedestrian fencing intended to stop illegal immigrants on foot, and 300 miles of vehicle barriers to stop drug smugglers on the southwest border. As of Sept. 30 of this year, 145 miles of fence were complete.
SOURCE: The Arizona Republic
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Second Report NBC News
SAN DIEGO, CA (NBC) -- The U.S. Border Patrol has released photos of attacks on agents that they say have led to the use of pepper spray and tear gas in Mexican border neighborhoods.

Officials said that escalating violence at the U.S.-Mexico border is forcing agents to take new measures, and the new tactics are creating controversy.