Liz Truss said “the jury is out” on whether French President Emmanuel Macron is Britain’s “friend or foe” at a Conservative leadership campaign event Thursday.

The hot favorite to become Britain’s new prime minister next month vowed to judge Macron by his “deeds not words” in her cross-Channel dealings as leader.

Her comments will only add further tensions to the stormy Anglo-French relationship, which has suffered badly since Britain voted to leave the EU in 2016.

Macron has endured a difficult relationship with the current outgoing U.K. prime minister, Boris Johnson, while Truss has been heavily criticized in EU capitals for her plans to rewrite parts of the Brexit divorce deal related to trade in Northern Ireland.

Asked directly at a hustings event in Norfolk, England Thursday evening whether Macron was “friend or foe,” Truss replied: “The jury is out. But if I become PM, I’ll hold him to deeds not words.”

Truss’ leadership rival, former U.K. Chancellor Rishi Sunak, described Macron as a “friend.”

Truss is widely expected to win the Conservative leadership contest when the result is announced on September 5, becoming the U.K.’s third female prime minister the following day.