'There is never a justification for this type of attack, the attempted murder of a private citizen on the soil of a sovereign nation, and we are outraged that Russia appears to have again engaged in such behavior.
'Russia continues to be an irresponsible force of instability in the world, acting with open disregard for the sovereignty of other states and the life of their citizens.'
He added that those responsible 'must face appropriately serious consequences.'
Tillerson made the remarks during his trip to Africa just hours after the the White House broke a week-long silence to condemn the chemical attack, but declined to mention Moscow.'
Trump repeatedly crossed swords with the former Exxon Mobil executive, including a public episode in October where the president chided him on Twitter for 'wasting his time trying to negotiate with Little Rocket Man' – a reference to North Korean dictator Kim Jong-Un.
Foreign policy veterans said at the time that they couldn't recall an instance where a sitting president had undermined his secretary of state in such a humiliating fashion.
But five months later the president himself accepted Kim's invitation for a face-to-face meeting over the hermit kingdom's nuclear missile program.
Tillerson raised eyebrows in Washington last year with reports that he had called Trump a 'moron' following a national security meeting in July about America's nuclear posture.
He never directly denied making the caustic remark, leaving that to a State Department spokeswoman. Trump said the same day that he had 'total confidence in Rex.'
Later that month, newly installed White House Chief of Staff John Kelly and Secretary of Defense James Mattis begged Tillerson to stay on.
The following month, after Trump angered Americans on both sides of the aisle with tone-deaf comments about the role of neo-Nazis in a Virginia race riot, a furious Tillerson declined to defend him.
'The president speaks for himself,' Tillerson said at the time during a 'Fox News Sunday' interview.
Even then, the White House outwardly professed comfort with Tillerson and confidence in his abilities.
Haspel will need to face a Senate confirmation hearing.
Pompeo will not, because the Senate confirmed him as the CIA director just three days into the Trump administration.
Trump said that his incoming secretary of state 'has earned the praise of members in both parties by strengthening our intelligence gathering, modernizing our defensive and offensive capabilities, and building close ties with our friends and allies in the international intelligence community.'
'I have gotten to know Mike very well over the past 14 months, and I am confident he is the right person for the job at this critical juncture,' he added.
'He will continue our program of restoring America’s standing in the world, strengthening our alliances, confronting our adversaries, and seeking the denuclearization of the Korean Peninsula.'