Story highlights Doctors Without Borders releases reports on two airstrikes that killed 20

The attacks caused the humanitarian organization to pull out of Yemen

(CNN) Doctors Without Borders said there was no legitimate reason for attacks on two medical facilities it supported in Yemen that killed 20 people and caused the group to pull out of the country.

On Monday the humanitarian group -- also known as Médecins Sans Frontières (MSF) -- released the results of investigations into airstrikes on a hospital in Abs in August and on a clinic in Taiz last December.

MSF said its investigation showed that "the neutrality and impartiality of the facilities had not been compromised before the attacks and therefore there was no legitimate reason to attack them."

The aftermath of the hospital attack in August

It also said: "The details of the incidents documented in these two reports are unambiguous indicators of how war is being waged in Yemen, where there is an utter disregard for civilian life by all warring parties."

In both attacks "the bombings hit fully functioning health facilities and the protected nature of the medical mission was not respected," it added.

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