The incident occured hours before dawn on Wednesday, a security official said.
Officers said they were investigating who was behind the raids in Nigeria's "Middle Belt", where the country's largely Muslim north and Christian south meet - a common flashpoint for violence.
Islamist Boko Haram rebels based in the remote northeast showed their reach in May by setting off bombs in Plateau state's capital Jos, around 300 miles from their strongholds.
(READ MORE: Blast in Nigerian city Jos kills at least 10)
They have killed thousands since starting a five-year-old campaign to carve out an Islamist state.
Plateau state has also seen thousands killed in violence between largely Christian Berom farmers and Muslim Fulani cattle herders over the past decade.
"Gunmen stormed the villages of Tanjol and Tashek ... and shot sporadically in the air, then killed eight people," said Captain Iweha lkejichi, from the area's joint task force combining army and police. The attackers torched one church and several houses, he added.
(READ MORE: West Africa leaders vow to wage "total war" on Boko Haram)
Police spokesman Dominic Esin said nine people were killed and two churches burned down in the attacks.