Beijing police have cracked the most serious gun-related case in the capital in two decades.

After receiving a tip from a navy officer, police in Beijing's Yanqing county detained five suspects and seized more than 20 guns before Spring Festival, Xinhua News Agency reported on Monday.

The navy's technical team had been inspecting the county since the end of last year to ensure residents were safe during the Spring Festival, which fell on Feb 19, the report said.

An officer later received reports of suspected gunshots in a community and some residents found explosive devices, it said.

Police arrested five people after an investigation and confiscated more than 20 guns, including air guns and shotguns, as well as thousands of rounds of ammunition, the report said, adding that it was the most serious gun-related case in the city in 20 years.

The county's public security bureau refused to disclose more details on Monday.

"China places a lot of importance on stopping gun-related cases, but the offenses, in fact, have still been serious," said Wu Ming'an, a law professor at China University of Political Science and Law.

Owning, using, making, transporting and purchasing guns are forbidden under the current Criminal Law and offenders face heavy punishment, Wu said, adding that in severe cases they may be sentenced to death.

In a nationwide campaign, police destroyed three gun-purchasing networks, detained 212 suspects and seized more than 350 guns, according to a statement from the Ministry of Public Security.

The police also seized more than 68,000 bullets and more than 2,400 accessories used for making guns, the statement said, adding that most offenders learned how to make guns via online forums and QQ, an instant messaging tool.

Wu said that some people bought parts for guns on the Internet and then assembled them in private workshops.

He approved of a rule banning individuals from posting information about dangerous goods online.

"It's good to see our police have cooperated with other authorities to boost gun control," he added.

Liu Tao, an associate professor at the People's Public Security University of China, suggested increasing the police investigating gun-related cases.