PARIS (AP) — The Latest on British Prime Minister Boris Johnson's effort to reopen Brexit talks on European trip (all times local):

11.00 a.m.

A group of U.S. legislators has written Prime Minister Boris Johnson, warning him that any trade deal with the United States is "highly unlikely" if the historic Good Friday accord is weakened.

The Congressional Friends of Ireland, a group in the U.S. Congress which promotes peace and reconciliation in Northern Ireland, wrote the letter to express its concern about British efforts to leave the European Union potentially resulting in a hard border between Northern Ireland and Ireland.

The letter notes that America is guarantor of the deal and says "any weakening of the Good Friday Agreement or threat to the 310-mile (500-kilometer) seamless border would make the prospect of a future US-UK trade deal highly unlikely."

The letter warns that the peace process is "still fragile and needs to be nurtured."

10.00 a.m.

British Prime Minister Boris Johnson is expected to find little support for his drive to reopen Brexit negotiations when he meets with French President Emmanuel Macron on the second stop of his European tour.

Johnson was buoyed Wednesday by German Chancellor Angela Merkel, who raised the possibility that a negotiated departure from the European Union may still be possible if Britain comes up with alternative plans for the Irish border within 30 days.

But Macron has already dampened expectations for meetings later Thursday, saying renegotiating the Brexit deal is "not an option." Johnson is seeking concessions to win support in Parliament where he has a one-seat majority.

Macron says: "We must help the British deal with this internal democratic crisis but we mustn't be hostage to it nor export it."