Dozens of US Democrat lawmakers protested Washington's unilateral policy of using lethal force around the world over successive administrations spanning the past two decades, which has cost the lives of as many as 48,000 civilians across seven countries.

The petition called on the Biden administration to "review and overhaul" US counterterrorism policy to center human rights and the protection of civilians and align with US and international laws - an acknowledgment that the United States had not been complying with international laws.

"Over successive administrations spanning nearly two decades, presidents have claimed virtually unilateral power to use lethal force around the world and without congressional authorization, killing not only armed actors but also innocent civilians - even American citizens," the letter read.

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Without reform, the letter argued, "The status quo will continue to undermine counterterrorism objectives, produce significant and strategic costs, and erode the rule of law and the United States' image abroad."

The letter, signed by 50 members of Congress, called on the Biden administration to reform the system that saw at least 14,000 airstrikes conducted by UAVs since 2002, which claimed the lives of at least 2,200 civilians, including 450 children. The letter said the numbers could even be higher than reported due to several circumstances.

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It also highlighted that despite the US launching its lethal operations under the guise of targeting "terrorism suspects" who "threaten US national security," US drone strikes have led to "unintended and deadly consequences - killing civilians and increasing anger towards the United States," in too many instances.