WASHINGTON, May 9 (Reuters) - A U.S. auto safety agency

said on Thursday it has "significant safety concerns" over Ford

Motor's ( F ) recall of more than 42,000 SUVs over concerns fuel

leaks could lead to an engine fire.

The National Highway Traffic Safety Administration (NHTSA)

said last month it was investigating the adequacy and safety

consequences of Ford's proposed recall remedy for 2022-2023

model year Bronco Sport and 2022 Ford Escape SUVs with 1.5L

engines.

In a letter to Ford made public Thursday, NHTSA said Ford's

plan "does not address the root cause of the issue and does not

proactively call for the replacement of defective fuel injectors

prior to their failure."