[1] From April 2003 to July 2004 he served as chief of staff - first deputy commander of a mechanized brigade of Ukrainian peacekeeping contingent of the multinational force in Iraq.

[1] In 2005 Muzhenko graduated from the Faculty training of operational and strategic levels of the National Defence Academy of Ukraine.

[1] In 2005 he was appointed Deputy Chief of Staff of the Army Corps of Ukrainian Ground Forces, a post he held till 2010.

[1] 20 May 2014 decree of the Acting President Oleksandr Turchynov appointed him first deputy head of the counterterrorist center at the Security Service of Ukraine.

[2] (According to Poroshenko) at the time his predecessor Mykhailo Kutsyn was suffering from shell-shock and a concussion and was staying at a hospital (he had been wounded while combating the 2014 insurgency in Donbas).