Ford has said a no-deal Brexit would be catastrophic for the firm's manufacturing operations in the UK and that it would do "whatever is necessary" to protect its business.
The comments come after a report the carmaker was stepping up preparations to move production out of the UK.
Ford declined to comment directly on The Times' report, but said it had long warned against a "hard Brexit".
The company is the latest carmaker to warn on the risks of a no-deal Brexit.
"Such a situation would be catastrophic for the UK auto industry and Ford's manufacturing operations in the country," the company said in a statement.
"We will take whatever action is necessary to preserve the competitiveness of our European business."
Ford employs 13,000 people in the UK at sites in Bridgend, Dagenham, Halewood and Dunton.
According to The Times' report, the firm told Prime Minister Theresa May on a telephone call with business leaders that it was preparing alternative sites abroad.
During the call Mrs May confirmed reports that the government was preparing a package of financial support for businesses affected by a no-deal Brexit but declined to elaborate, The Times said.
Other companies on the call delivered the same warning as Ford, the report said.
Ford is the latest carmaker to sound the alarm on Brexit after Nissan said last week it would no longer build its X-Trail car in Sunderland, in part because of Brexit uncertainty.
In January, Jaguar Land Rover, the UK's biggest carmaker, said it would cut 4,500 jobs in the UK, citing geopolitical issues, regulatory disruptions, and Brexit uncertainty. Toyota has also urged the government to avoid a no-deal scenario.
In addition to Brexit worries, the car industry faces a slump in sales of diesel cars and a slowdown in China.
Last month, the Unite union said Ford aimed to cut almost 1,000 jobs at its Bridgend plant by 2021 because of challenging market conditions. The carmaker declined to confirm the figures but said it was consulting with unions.
The government has said the best way to provide certainty to industry is for MPs to back the prime minister's Brexit deal.