The ''permitless carry'' gun law came into effect in Oklahoma on Friday, media reported. The law allows Oklahomans over 21 to open or conceal carry a gun without a license or special training, except for those convicted of certain crimes and non-residents.
Oklahoma's authorities, however, warned that firearms are still restricted at public buildings, including bars, schools, sporting events and also on college campuses.
The law takes effect after Rep. Jason Lowe's petition against ''permitless carry'' was blocked by Oklahoma's Supreme Court earlier this week.
The "permitless carry'' law was signed by Republican Gov. Kevin Stitt in February.
US citizens are allowed to keep and bear arms in accordance with the Second Amendment, therefore, this right is often referred to as ''constitutional carry".