WASHINGTON, April 27 (Xinhua) -- The U.S. Defense Department has stepped up efforts since the Sept. 11, 2001, attacks to gather intelligence within U.S. borders, aimed at both protecting military facilities and keeping an eye out for any threat on American soil, The Wall Street Journal reported Thursday.

    After Sept. 11, the Bush administration declared the continental United States a theater of military operations for the first time since the Civil War, creating a demand to better research potential threats to American forces at home, the report said.

    Several parts of the Defense Department are building large databases of information from sources such as local police, military personnel and the Internet, and in doing so, the military is edging toward a sensitive area that has been off-limits to it since the 1970s: domestic surveillance and law enforcement, according to the report.

    One widely reported part of the new information battle is the National Security Agency's wiretapping of calls without a warrant between people in the United States and suspected terrorists overseas. The NSA is part of the Defense Department.

    The military justified the gathering of domestic intelligence in part by relying on a key distinction between "receiving" information and "collecting" it. Military regulations over the past few decades have generally barred using soldiers to gather information on American citizens, but military officials have interpreted the rules to mean that receiving information from the police or federal agents is acceptable, the report said.

    The military moves face both political and practical objections, according to the report. Civil libertarians fear a return to the Vietnam War era, when military personnel collected information on more than 100,000 Americans, infiltrated church youth groups and posed as reporters to interview activists. And critics say the receiving-versus-collecting distinction makes little sense if the Pentagon is taking in huge amounts of data, organizing it, analyzing it and using it to influence law enforcement.

    The Pentagon has monitored more than 20 antiwar groups' activities around the country over the past three years, the Journal report said. It has reviewed photographs and records of vehicles and protesters at marches to see if different activities were being organized by the same instigators.

    The military's secret monitoring of dissidents during the Vietnam War led to a slew of laws, regulations and executive orders that pushed the military out of domestic spying and created walls between domestic and foreign intelligence, the report said. Enditem