The UK Royal Air Force's (RAF) Typhoon fighters have intercepted five Russian aircraft near Estonian border.
Four Typhoon jets carrying pilots from II (Army Co-operation) Squadron were launched after detecting five unidentified aircraft flying in international airspace along the northern and western borders of Estonia.
The aircraft were identified as four Su-27 Flanker fighters and an IL-20 Coot-A Reconnaissance aircraft.
UK Defence Secretary Michael Fallon said: "For the second time in a week, the RAF have been on hand to respond to Russian activity at a moment's notice.
"24 hours a day, seven days a week, we will continue to secure the Baltic skies on behalf of NATO and our allies."
UK has deployed four Typhoons to the Amari Air Base in Estonia, last month, to take part in Nato's Baltic Air Policing (BAP) mission until the end of August this year.
The Typhoon jets are operating alongside Portugese F-16 multirole fighter aircraft based in Siauliai in Lithuania.
140 Expeditionary Air Wing RAF commanding officer wing commander Gordon Melville said: "Today we again demonstrated the RAF's ability to launch our quick reaction alert aircraft quickly to investigate aircraft operating in the vicinity of the Baltic states as part of our support to the NATO Baltic Air Policing mission.
"Several years' experience operating in this area indicates that we can expect further similar activity in the months ahead.
"Our mission continues, and our NATO allies can stand assured of the UK's full support for their defence."
Previously, Typhoon fighters were scrambled 17 times, and intercepted more than 40 Russian aircraft.
Image: Royal Air Force Typhoon fighter jets in flight. Photo: courtesy of Crown Copyright.