BEIJING, May 12 -- Beijing police deployed 150 armed patrol vehicles to city streets Monday to maintain stability in the capital.

The armed vehicles will become the principal force in countering street terrorism and violence in Beijing.

Sources with the Beijing Public Security Bureau said the patrols will mainly be responsible for incidents involving guns, bombs, mass violence or terrorism.

The vehicles, stationed at main intersections with heavy traffic, will be a deterrent to terrorists. Each vehicle will be deployed with nine policemen and four assistants. The patrol forces will cover the main streets of Beijing, with each vehicle covering no more than three kilometers.

The police are required to reach the scene of any incident within three minutes after receiving a report.

The move is an escalation of the anti-terror fight at a time when attacks are spreading. It came shortly after the country's Minister of Public Security, Guo Shengkun, had urged deployment of as many police officers as possible at key public venues at crucial times.

"We should keep the pressure on and dare to strike heavy blows... and firmly foil such plans before they become realities," Guo said during an inspection in central China's Hunan Province from May 6 to 9.

Mei Jianming of the Chinese People's Public Security University (CPPSU), said the measures demonstrated the determination of the government to fight terrorism.

"It conveys a signal of deterrent to the potential terrorists and violent attackers," Mei said.

China has in recent years seen a string of violent attacks on police, government organs as well as on civilians, with most in northwest China's Xinjiang Uygur Autonomous Region.

Three people were killed and 79 others injured in an attack on April 30 at a railway station in Urumqi, capital of Xinjiang. In an incident last June, rioters killed 24 people at the region's Lukqun Township.

Since last year, the attacks have spread beyond Xinjiang to the country's southwest region as well as to Beijing. On March 1, assailants killed 29 civilians and injured another 143 at a railway station in the southwestern city of Kunming.

Terrorist activities are expanding to more areas with government agencies, military and police forces as their main targets, according to a report by the Center for International Strategy and Security Studies under the University of International Relations and Social Sciences Academics Press.

Terrorists in China tend to use primitive weapons, such as knives and gasoline, as guns are strictly controlled. "The use of knives and gasoline by terrorists has undoubtedly added difficulties to combatting terror," said Li Wei of the China Institute of Contemporary International Relations (CICIR).

On Friday, the Beijing government published a notice on its website, requiring residents who buy gasoline in bulk to register their names and intended use of the fuel at police stations.

Beijing police have run at least three anti-terror drills over the past three weeks. The latest, on Thursday involved a police helicopter and more than 30 vehicles from SWAT units, traffic control and other emergency response departments.

Li of the CICIR however noted that although the military can squeeze terrorists, it can hardly eradicate terrorism. "Military or police deterrents can only serve as a part of the whole anti-terror strategy," Li added. It is equally important to strengthen intelligence as well as collaborating with other countries in the fight against terrorism.

Apart from these concrete measures, the CPPSU announced recently that it would recruit 80 students across the country for a new anti-terrorism course.

Major units of the course include research on terrorist organizations, international cooperation, risk assessment, reconnaissance and evidence collection.