A bomb went off near an international airport in Indonesia's easternmost province of Papua late Sunday, police said, but no one was injured and there was little damage.

The blast, which occurred a half-mile from the runway at Moses Kilangin airport, came days after near simultaneous explosions on a road leading to a massive U.S.-owned copper and gold mine in the same district.

Police chief Maj. Gen. Bagus Ekodanto would not say if the events were related, but other officials noted that all three makeshift bombs were made out of old mortars.

"Whoever did this, is trying to create unrest and to get international attention," Ekodanto said, as an elite anti-terrorism unit and bomb squad rushed to the scene.

Papua is home to separatist rebels who have long denounced the mine operated by Freeport-McMoRan Copper & Gold Inc. as a symbol of Jakarta's rule over the region.

A little-known group calling itself the West Papua National Army started circulating pamphlets early last week demanding the mine's closure, but police have refused to speculate who was behind any of the attacks.

Ekodanto said Sunday's blasts occurred in an empty field and that no one was hurt.

Part of the mortar hit a small building containing electrical equipment, creating a loud explosion, said Col. Paulus Waterpau, a senior detective. Residents said they could hear it three miles (five kilometers) away.

Freeport's mining complex is one of the world's largest single producers of copper and gold, the company says on its Web site. It says that open-pit mining at the site began in 1990 and is expected to continue until mid-2015.

The Grasberg mine has seen violent worker protests in the past, and environmental groups accuse the company of alleged pollution and stripping the desperately poor province of its natural resources.

No one was injured in Friday's pre-dawn bombs, which targeted a bridge and security post leading to the mine.