The US government could be guilty of war crimes in Somalia after evidence of civilian casualties was uncovered in an investigation led by Amnesty International.

The investigation found that US airstrikes from both drones and manned aircraft killed at least 14 civilians and injured eight more people in just five of more than 100 strikes in the past two years.

"The public needs to understand that the US government really doesn't do a very good job of investigating who it's killed. We've seen this repeatedly now," an expert at Amnesty International told INSIDER.

"The attacks appear to have violated international humanitarian law, and some may amount to war crimes," the Amnesty International report said.

The US military could be guilty of war crimes in Somalia, according to a new report that challenges what the government has said about civilian casualties from its bombing campaign against al-Shabab — an al-Qaida affiliate — in the African nation.

The investigation, conducted by Amnesty International, found that US airstrikes from both drones and manned aircraft killed at least 14 civilians and injured eight more people in just five of more than 100 strikes in the past two years.

"The attacks appear to have violated international humanitarian law, and some may amount to war crimes," the Amnesty International report said.

The US Africa Command, or Africom, one of the Pentagon's 10 combatant command centers worldwide, "repeated its denial that any civilians have been killed in its operations in Somalia" when presented with Amnesty International's findings.

Read more: Trump inherited Obama's drone war, and he's significantly expanded it in countries where the US is not technically at war

Amnesty International conducted more than 150 interviews with "eyewitnesses, relatives, persons displaced by the fighting, and expert sources," while "rigorously" analyzing "satellite imagery, munition fragments, and photos from the aftermath of air strikes."

Amnesty could not sufficiently corroborate reports of civilian casualties in each one of the dozens of strikes in Somalia that it examined, but it said in its report that the "civilian death toll may well be much higher."

The Department of Defense and US government "have not been honest about civilian casualties from its operations in Somalia," Daphne Eviatar, Amnesty International USA's director of security with human rights, told INSIDER.

The US has conducted dozens of strikes in Somalia under President Donald Trump, and it's not clear which were done under the Pentagon versus the CIA. Most drone strikes conducted by the Pentagon are required to be disclosed publicly, but the US intelligence community does not operate under the same rules.

"Africom has consistently said, despite dozens of airstrikes every year, that there have been zero civilian casualties" in Somalia, Eviatar said, adding that this assertion is "just not credible."

Amnesty International was "very suspicious" of the military's consistent claims it wasn't killing any civilians in airstrikes, Eviatar said.

Read more: Trump quietly rewrote the rules of drone warfare, which means the US can now kill civilians in secret

"We'd been getting some reports from the ground that this wasn't the case," she added. "But we didn't know for sure until we went there and interviewed witnesses, looked at a ton of evidence, and realized that, in fact, there are children, farmers, and well-diggers being killed — people who are clearly not al-Shabab fighters."

The US government "needs to acknowledge" these civilian casualties, Eviatar said, adding that it looks like the military is engaging in what are known as "signature strikes" — strikes that target military-age males, even if the US isn't certain they have ties to militant or extremist groups. "That's completely unlawful," Eviatar said, adding that criticism on this practice led President Barack Obama to establish new rules designed to protect civilians.

Read more: US military says it killed roughly 60 'terrorists' in Somalia airstrike, the deadliest in a year

Trump has rolled back Obama-era rules on covert drone strikes and has overseen a drastic increase in the number of strikes in Somalia, expanding the shadow wars that began under Obama. Under Trump, the US conducted more drone strikes in Somalia in 2017 alone than the total number conducted in the African nation during Obama's entire tenure.

Amnesty's investigation comes on the heels of a decision from Trump to end an Obama-era rule for the US government to publicly report on civilian casualties from drone strikes. The reversal of that rule indicates there will be even less transparency on a program that was already virtually entirely out of the public eye.

Read more: America's year in war: All the places US armed forces took or gave fire in 2018

"The public needs to understand that the US government really doesn't do a very good job of investigating who it's killed. We've seen this repeatedly now," Eviatar said. "We saw it in Iraq, we saw it in Syria, and now we're seeing it in Somalia."

Responding to Amnesty's report, a senior White House official on Wednesday told INSIDER: "The United States Government is fully committed to complying with its obligations under the law of armed conflict; to minimizing, to the greatest extent possible, civilian causalities; and to taking appropriate action when civilian casualties unfortunately occur during military operations."

"In fact, the US government often imposes heightened policy standards that are more protective of civilians than the requirements of the law of armed conflict," the official added.

Experts have pointed to civilian casualties from drone strikes as a catalyst and recruiting tool for terrorism, which underscores why this is an issue that strongly influences the public, even though it might have little knowledge about it because of the secrecy surrounding these strikes.

In 2010, a man named Faisal Shahzad attempted to bomb Times Square in New York City. Shahzad cited drone strikes as his inspiration.