Conflict shows signs of entering new, more dangerous phase as additional 3,500 US troops arrive in the Middle East

US lawmakers responded to reports that the Pentagon is preparing for weeks of ground operations in Iran, as thousands of US troops assemble in the Middle East and the conflict showed signs of entering a new, more dangerous phase.

Officials told the Washington Post that a ground operation in Iran could be limited to raids by Special Operations forces and infantry troops, but it was unclear whether Donald Trump would approve any of the Pentagon’s plans.

Senator James Lankford, a Republican, told NBC’s Meet the Press that he had not ruled out supporting troops on the ground but that “we’ve got to be able to know what the objectives are and what they’re actually carrying out.”

Lankford, who serves on the Senate’s committee on intelligence, said it was important to “finish” the job but know “what boots we’re putting on the ground”.