Key developments on Feb. 19: Military: Russian troops killed wounded Ukrainian soldiers in Avdiivka after promising to evacuate themCommander: Some units of 3rd Assault Brigade were ‘completely surrounded’ in Avdiivka but managed to escapeNBC: Biden administration considering supplying Ukraine with long-range ATACMS missilesAir Force: Ukraine shoots down 2 Russian fighter jetsMedia: Ukraine may receive first F-16 jets in JuneThe Russian military pledged to evacuate wounded Ukrainian soldiers from the Zenit strongpoint in the town of Avdiivka and provide them with assistance but instead shot de…