Google and Apple have advised some employees on visas not to travel outside the US due to delays at embassies, Business Insider has learned. Both companies' outside counsels sent emails advising staff who require a visa stamp to re-enter the US not to leave the country because visa processing was taking longer than usual, according to copies of the memos reviewed by Business Insider.

"Please be aware that some US Embassies and Consulates are experiencing significant visa stamping appointment delays, currently reported as up to 12 months," the memo sent Thursday by BAL Immigration Law, which represents Google, says. The firm recommended that employees avoid international travel as they would "risk an extended stay outside the US."

A memo from Fragomen, a law firm representing Apple, sent to some visa holders at Apple last week similarly warned them not to travel. "Given the recent updates and the possibility of unpredictable, extended delays when returning to the U.S., we strongly recommend that employees without a valid H-1B visa stamp avoid international travel for now," the memo says. "If travel cannot be postponed, employees should connect with Apple Immigration and Fragomen in advance to discuss the risks."