Carla Lockhart, a DUP MP, has warned that the DUP could use its position to remove Michelle O'Neill as Northern Ireland's first minister.
The threat follows the Secretary of State's decision on Friday to ban the Portadown District Lodge from marching down the mainly nationalist Garvaghy Road. The move was welcomed by nationalist politicians but criticised by unionists.
O'Neill is among several Sinn Féin politicians who have confirmed receiving letters from the Police Service of Northern Ireland (PSNI) investigating protests over the Drumcree parading dispute. She has previously dismissed a call from the DUP to resign over the issue.
Speaking outside Drumcree Church on Saturday, Lockhart said her constituents were angry. "They're angry at the chief constable for allowing lawlessness to win, for allowing the mob to dictate," she said. "They're angry at the secretary of state for his intervention, but the most palpable anger is at Michelle O'Neill, this self-proclaimed 'first minister for all' for breaking the law flagrantly on the Garvaghy Road."
The dispute revives long-standing tensions around the annual Drumcree Orange Order parade, a traditional flashpoint between unionists and nationalists. The DUP's threat to remove O'Neill raises questions about the stability of the power-sharing executive.