At least 9 people were killed in militant attacks on oil and gas installations in Iraq on Sunday, security sources told EFE news.At least four workers linked to Iraq's North Oil Company were killed when armed attackers targeted a gas installation near the city of Kirkuk, sources said.The attackers placed explosive devices and fled before security forces encircled the area and launched a large manhunt in a bid to capture the armed group, Kirkuk security sources said.Later, five suicide attackers were killed at an oil field at Bai Hassan, about 20 kilometers northwest of Kirkuk.One of the bombers died immediately in a clash with security forces, while the other four were killed after they had succeeded in causing two oil reservoirs to explode and catch fire.The province of Kirkuk is known for its oil-rich reserves.