The group put on hold a €24mln contract with one airport following the US withdrawal from the Iran nuclear pact in May.
There are uncertainties over how suppliers might be affected by possible sanctions, but with European signatories still supporting the nuclear pact and Peter Fowler, chief executive, believes the airport deal can still go ahead.
“We remain hopeful that measures being put in place to protect EU companies against US extraterritorial actions will allow these projects to proceed.”
A second contract in Iran worth €2.6mln has also been put on hold.
Results for 2017 reflected the cost of Westminster’s exit from its Sierra Leone ferry business and the legacy of the Ebola crisis in the country.
"Both our Managed Services and Technology divisions are performing well and the Group closed its ferry operations from late September 2017 to focus on its core business. Our prospects have increased and operationally we have made significant progress," said Fowler.
Revenues in 2017 rose by 22% to £5.4mln (2016: £4.4mln) with £3.6mln from Managed Services (2016: £2.8mln) marking the end of the Ebola period in West Africa and resumption of passenger volumes.
Technology division revenues were £1.8mln compared with £1.6mln in 2016.
Statutory losses for the year were £6.1mln, including £3.7mln for now-closed business including ferries.
Westminster has also rolled over £2.25mln of convertible loan notes until at least June 2019.
Shares rose 8% to 13.75p.