KYIV, Ukraine (AP) -- A series of clandestine, against-the-odds helicopter missions to reach besieged soldiers are being celebrated in Ukraine as one of the riskiest, most heroic feats of military derring-do in the four-month war against Russia.

The flights delivered supplies and evacuated wounded during the last-ditch defense of the Azovstal steel mill.

It was surrounded by Russian forces in the brutalized city of Mariupol. Ukrainian troops were pinned down for weeks, their supplies running low, their dead and injured stacking up.

Ukraine's president first spoke of the sometimes deadly helicopter resupply missions only after Azovstal's defenders started surrendering in May.

The Associated Press has found and interviewed some of the wounded who were rescued from the death trap.