Armed Russian air force fighter jets have entered the Ukraine airspace, defense intelligence source have confirmed.
The deployment of armed fighter aircraft’s inside Ukraine is a serious violation, the Pentagon (Washington DC.) stated.
These violations, these escalations will have consequences, US Foreign secretary Kerry said.
These mistakes will have very expensive consequences, he added.
Russian fighter jets entered the Ukraine 
airspace severally in the past 24 hours in what intelligence officials view as a test on Ukraine radar systems and also a show of might and force.
Russia has increased its military presence along its border with Ukraine. The Russians are conducting military exercises by moving fixed wing and rotary aircraft and armored troops.
Kiev is accusing Moscow of trying to start another world war.Moscow’s foreign minister Lavrov has warned Kiev of serious recourse for the military activities on civilian population areas.
