UK accidentally sent military emails meant for US to Russian ally

British authorities have launched an investigation after officials mistakenly sent emails meant for U.S. military intelligence to the government in Mali, a Russian ally.

Officials from the U.K. Ministry of Defense were supposed to be sending emails to the Pentagon, but accidentally sent them to Mali’s government instead, the Times reported Thursday. The mistake was the result of a typo, as the Pentagon’s domain name is “.mil,” while Mali’s is “.ml.”

The Ministry of Defense said Friday they were investigating the incident.

“We have opened an investigation after a small number of emails were mistakenly forwarded to an incorrect email domain,” a spokesperson for the ministry said, Reuters reported.

According to the Times, while most emails sent to Mali were innocuous — containing information such as dates when the employees from the foreign ministry were on holiday — others contained “detailed descriptions” of British research into hypersonic missiles.

However, the Ministry of Defense said the Times’ claims were misleading.

“This report misleadingly claims state secrets were sent to Mali’s email domain. We assess fewer than 20 routine emails were sent to an incorrect domain & are confident there was no breach of operational security or disclosure of technical data,” the ministry said Friday. “An investigation is ongoing. Emails of this kind are not classified at secret or above.”

According to Reuters, the spokesperson said all sensitive information is shared “on systems designed to minimize the risk of misdirection.”

“The MOD constantly reviews its processes and is currently undertaking a program of work to improve information management, data loss prevention, and the control of sensitive information,” they said.

Earlier this month, an investigation by the Financial Times found that millions of emails meant for the Pentagon have been sent to Mali as a result of the same typo. Some of these emails included sensitive information, such as diplomatic documents, tax returns, passwords and officers’ travel details, the investigation found