According to the lawsuit, the two men were en route from Venezuela to their home country of Trinidad and Tobago when their boat was fired upon on October 14, NBC News reports.
The Pentagon claims that six people were killed in the attack and that all were "narco-terrorists."
But in the lawsuit, relatives claim that the two, aged 26 and 41 respectively, were fishermen.
Pentagon figures show that a total of 126 people have been killed since the US began its attacks in September last year. The Trump administration has claimed before Congress that the attacks are part of an armed conflict against drug cartels.
This reasoning is rejected in the lawsuit, which states that there is no armed conflict and that the laws of war therefore do not apply.
