The US government has formally commenced the process through which it hopes to renegotiate the terms of the North American Free Trade Agreement (NAFTA).

Congress has been officially notified that president Donald Trump intends to renegotiate the trade pact with Canada and Mexico, with the stated aim of supporting higher-paying jobs in the US and growing the economy by improving US opportunities for trade.

Negotiations will begin on August 16th at the earliest, with newly-appointed US trade representative Robert Lighthizer set to consult with lawmakers on the position the US should take in negotiations over the next 90 days.

Mr Lighthizer said his office "will now continue consultations with Congress and American stakeholders to create an agreement that advances the interests of America's workers, farmers, ranchers and businesses".

President Trump has repeatedly spoken of a need to overhaul NAFTA, which he has sharply criticized for damaging the US manufacturing sector and paving the way for a mass migration of jobs to Mexico.

It was previously thought that this may lead to the US pulling out of NAFTA completely, but the decision has now been taken to renegotiate the deal instead.