The disruption in oil supplies has caused shortages and concerns in several African countries.
The Maldives is threatening international legal action to press its claim for control of the Chagos Islands.
It come after a minister said the UK is discussing "concerns" with the US, after President Trump criticised the deal.
The president says the UK must "not give away" Diego Garcia, shortly after the US appeared to have backed the deal.
A court upholds a challenge about the lawfulness of the orders to remove four men who travelled to the territory.
US Department of State says it supports the UK's decision to "proceed with its agreement with Mauritius concerning the Chagos archipelago".
Investors are spooked by an order on a 2018 stake sale and fear it could open up old transactions to tax scrutiny.
The prime minister says he has discussed the deal with Donald Trump, but there are concerns in Whitehall the US could withdraw support for the agreement.
The Conservatives have raised further concerns after Donald Trump described the agreement as a "great act of stupidity".
