Seoul police said Friday they had arrested five people for selling scrapped US-made military equipment, including a missile launcher, sought by South Korean weapons enthusiasts on the black market.

The police released pictures of the seized items, which included a missile, a portable anti-aircraft missile launcher, gas masks, night vision goggles, bulletproof vests, walkie-talkies and camouflage uniforms.

"Such military uniforms could be used by terrorists... They would also make it difficult to identify friends from foes," the Seoul Metropolitan Police Agency said.

The equipment is believed to have been disposed of by US army bases in the country.

Since 2000, a 54-year-old man and three others arrested had been circulating the items on black markets in Seoul and the northern city of Dongducheon, which hosts Camp Casey, one of the largest US military bases in South Korea.

The fifth man operated a store and an online shopping mall specialising in military equipment and fake field jackets produced in China.

Many of the scrapped items were purchased as souvenirs, but some could be brought back into use, the police warned.

The seized stinger missile launcher had been deactivated after its antenna and batteries were removed, and a rocket missile could be activated if loaded with propellant powder.