WASHINGTON, Dec 20 (Reuters) - U.S. lawmakers early Tuesday included a proposal to bar federal government employees from using Chinese app TikTok on government-owned devices in a key spending bill.The Senate last week voted on a bill sponsored by Republican Senator Josh Hawley to bar federal employees from using the ByteDance-owned short video app on government-owned devices.The bill gives the White House Office of Management and Budget 60 days "to develop standards and guidelines for executive agencies requiring the removal" of TikTok from federal devices.The proposal last week won the backing of House Speaker Nancy Pelosi and House Republican Leader Kevin McCarthy.Many federal agencies, including the White House and the Defense, Homeland Security and State departments, already ban TikTok from government-owned devices."