U.K. Prime Minister Theresa May attends a press conference in Rome | Franco Origlia/Getty Images Theresa May favors unique EU-UK arrangement post-Brexit ‘We should be developing the model that suits the UK and the EU,’ British PM said in Rome.

U.K. Prime Minister Theresa May will look at Britain's future trade relations with the European Union with "an open mind," she said Wednesday, following a meeting with Italian Prime Minister Matteo Renzi.

"I think we should be developing the model that suits the U.K. and the EU. Not adopting, necessarily, a model that is on the shelf already," May told journalists in Rome, according to the BBC.

When asked whether she agreed with International Trade Secretary Liam Fox, who said Tuesday that the U.K. would likely seek a free trade agreement with the EU rather than remain part of the bloc's customs union, May said she was "looking at this with an open mind."

Fox told the Wall Street Journal that London would probably avoid a customs union, which could limit its ability to negotiate lower tariffs with other trading partners.

For his part, Renzi said the negotiations around Britain's exit from the EU would be "painful," while saying his country would do "its utmost to collaborate and support the process."

May and Renzi also discussed cooperation in the fight against terrorism, in the wake of Tuesday's murder of an elderly priest in France by two terrorists, as well as the situation in Syria and Libya. The two leaders "secured agreement to extend the EU’s naval operation to include capacity building of the Libyan coastguard," May said.

The British prime minister said she had chaired the first meeting of the Cabinet Committee on Britain's exit from the EU Tuesday "to prepare and plan for an orderly departure."