South Korea's intelligence agency says it believes the Palestinian Islamic group Hamas is using a type of rocket-propelled grenade launcher made by North Korea.

The National Intelligence Service provided the assessment on Monday, along with a photo of the launcher allegedly used by Hamas. It says a component of the weapon has Korean characters, although they are not visible in the photo.

The agency says it is collecting detailed evidence of North Korea's suspected supplies of weapons to Hamas, including the volume and timing of transactions.

South Korea's military suggested last October that there were arms trade links between Hamas and North Korea.

It said rocket launchers owned by Hamas and spent artillery shells the group is believed to have used were likely made in North Korea.