Ford will be in the UK for "quite some time" despite concerns about the impact of the Brexit vote, the company's chief executive has said.
However, Mark Fields told the BBC he could not guarantee manufacturing would stay once Britain leaves the EU.
He repeated Ford's position that a free trade agreement needs to be reached with the European Union.
Ford employs 13,000 people in the UK, with engine production lines in Dagenham and Bridgend.
The US company has been reducing its manufacturing capacity in Europe in recent years and stopping making vehicles in the UK in 2013 after more than 100 years.
Mr Fields said: "We need to make sure that all of our facilities around the world are globally competitive.
"We are very proud to be in the UK and we are going to be in the UK for quite some time but it's going to be really important, particularly because Article 50 is now triggered, that from our standpoint there needs to be free trade between the UK and the continent."
Asked if Ford would keep manufacturing in the UK he said: "I can't guarantee anything, nobody can guarantee anything over many many years."
Industry trade body the Society of Motor Manufacturers and Traders said in January that uncertainty around Brexit and the UK's future trading arrangements had hit investment in the car sector.
Although Toyota has announced new investment, the Japanese car giant said "continued tariff-and-barrier free market access between the UK and Europe... will be vital for future success".
Nissan announced it would build the new Qashqai and the X-Trail SUV at its Sunderland plant following government "support and assurances" after the Brexit vote.
Mr Fields said: "I think our intent is making sure that our UK business remains very strong and that's why we're engaging with the governments to be able to say here's what we think we need to make sure that that remains a possibility and we stay across the continent and in the UK and we have a healthy business in Europe."
He was speaking in China, where Ford has unveiled plans to substantially increase its electric vehicle manufacturing.
But Mr Fields insisted there was a future for diesel powered vehicles, despite moves to introduce new emissions based charges in cities like London.
He also called on China to change the way it treats foreign firms like his and give them fairer access to the world's biggest automotive market.