WASHINGTON, July 16 (Xinhua) -- U.S. non-essential travel restrictions across its borders with Canada and Mexico will be extended for another month due to the COVID-19, U.S. Acting Homeland Security Secretary Chad Wolf said on Thursday.

Wolf tweeted that "based on the success of the existing restrictions and close collaboration with Mexico and Canada, @DHSgov will continue to limit non-essential travel at our land ports of entry with Canada and Mexico until Aug 20."

"Close collaboration with our neighbors has allowed us to respond to #COVID19 in a North American approach and slow the travel-related spread of the virus," he added.

The border restrictions were first implemented on March 21.

Over 3.5 million confirmed COVID-19 cases have been reported in the United States, with over 137,000 deaths, according to the latest data from Johns Hopkins University.