Niniek Karmini, Jakarta – A bomb exploded Sunday near an airport built by a US gold mining giant in Indonesia's restive Papua province, police said. No one was injured and there was little damage.

The blast half a mile from the runway at Moses Kilangin airport came days after two mortars were detonated on a road leading to the massive mine operated by Freeport-McMoRan Copper & Gold Inc.

"Whoever did this is trying to create unrest and to get international attention," said police chief Maj. Gen. Bagus Ekodanto, 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 PT Freeport Indonesia, a subsidiary of the New Orleans-based company. They see it as a symbol of Jakarta's rule over the region.

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

The police chief would not say whether Sunday's bomb was related to the explosions on Friday. But other officials noted that all three makeshift bombs were made out of old mortars.

Ekodanto said Sunday's blasts occurred in an empty field and that no one was hurt. Part of the mortar hit a small electrical depot, creating a loud explosion, said Col. Paulus Waterpau, a senior detective. Residents said they could hear the blast three miles away.

Access to the airport was cut off and witnesses said Freeport's mine in Timika also was under heavy security.

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

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

Separatist rebels were blamed for a 2004 ambush on a road leading to the mine that left two Americans dead. Indonesian security forces were initially suspected of taking part in those killings to extort higher protection payments from Freeport.

[Associated Press Writer Irwan Firdaus contributed to this report from Jakarta.]