Four is the usual number of fighters conducting the mission from the airbase in nothern Lithuania.
Seven US fighter jets in late October landed at the Siauliai military airfield for a training deployment, joining another seven American aircraft that had patrolled Baltic airspace from Lithuanian since September. The drills ended last Friday.
"Ten US fighters departed from the Aviation Base in Siauliai on Friday evening," Captain Ieva Gulbinienė, public relations officer at the Lithuanian Air Force base, told BNS on Monday.
"Four fighters stayed, which is the standard number of aircraft on the air-policing mission," she added.
The United States in September reinforced the mission with additional fighter jets ahead of Zapad 2017, a large-scale military exercise held in Russia and Belarus that month.
Four Belgian fighters are currently carrying out the air-policing mission from Estonia.
Fighter jets from NATO member states have been patrolling the skies over Lithuania, Latvia and Estonia on a rotational basis since the three nations, which do not have fighter aircraft of their own, joined the Alliance in 2004.