In a Foreign Ministry statement, Ecuador described the air raids as a "violation of the state of Syria's sovereignty and a threat to its territorial integrity."
"The actions they carried out go against international rights, for they have not been recognized by the UN General Assembly nor authorized by the Security Council," read the statement.
Earlier this week, Washington and a coalition of Arab allies launched a series of airstrikes against the militants in Syria.
The attacks, however, have so far been ineffective in stopping the militants. The raids have prompted the terrorist to increase the number of their men and weapons.
"It is imperative that any military action get proper approval from the international community. Recent history teaches us that measures that are unilateral, as well as unlawful, exacerbate instability in those territories," the statement added.
Venezuelan President Nicolas Maduro recently rejected the air raids at the UN General Assembly. He said the Western countries are to blame for the current crisis in the Middle East.
Maduro said that any military action must respect the sovereignty of independent nations. Maduro also praised Damascus in dealing with the militant groups.