The Friends of Ireland caucus in the US Congress has expressed concern about fresh political divisions in the North, saying they risk undermining the peace process and threaten institutions set up under the Belfast Agreement.

In one of its strongest statements in years, the 53-strong political grouping of senators and members of Congress called on Northern political leaders to re-engage in talks and “avoid any further potential negative impact on the peace process, the institutions and on investment and tourism in the region”.

The caucus urged the Northern parties to re-enter discussions on the proposals of former US diplomat Richard Haass to reach an "early agreement" on the contentious issues of parades, flags and the past.

The US politicians were reacting to the threat of protests from Orange, unionist and loyalists leaders at all governance levels if the British government does not set up a commission of inquiry into the decision to ban an Orange Order parade in the Ardoyne area of Belfast and into the wider issue of parading.

In a joint political statement the Capitol Hill caucus urged Northern Ireland's five main political parties "to show leadership and determination to return Northern Ireland to stable and effective government in accordance with the Good Friday agreement".