The top US business lobby on Monday urged Britain to conclude a bilateral trade deal with the European Union as quickly as possible to remove uncertainty that is limiting investment flows and could pose risks to its trade talks with the United States.

The US Chamber of Commerce, in a series of recommendations issued ahead of the start of US-UK trade talks on Tuesday, said US firms had invested more than $750 billion in Britain, in large part to secure access to the larger EU single market before Britain voted to leave the bloc.

The group underscored its view that London should redefine its ties to Brussels before working out trade deals with other countries, but said there were opportunities for Britain and the United States to advance global standards in the digital economy, financial services, and emerging technologies.

The business group also urged Britain and the United States to work to eliminate all tariffs in their bilateral trade discussions, saying that would boost the long-term outlook for both countries.