Japan's information technology agency has detailed a new cybercrime aiming to swindle businesses out of money via emails that appear to have been sent from partner companies, sources said Sunday.

The Information-Technology Promotion Agency looked into four cases in which domestic companies' email systems were compromised, a threat that has emerged on a global scale. Money was stolen in two cases, although the agency withheld the amount and name of the companies.

According to the U.S. Federal Bureau of Investigation, about 22,000 such cases were reported in the United States and elsewhere between October 2013 and June 2016, causing a combined loss of about $3.1 billion. The average amount stolen in each case was approximately ¥16 million.