Top Trump administration officials told lawmakers Tuesday that U.S. military deployments in the Middle East were purely defensive and not aimed at provoking a war with Iran, amid growing concerns in Congress about a possible military conflict.

Secretary of state Mike Pompeo and secretary of defence Pat Shanahan on Tuesday briefed US Senate and the House of representatives on the “credible intelligence” that led to recent escalation, with the US deploying an aircraft carrier group, bombers and anti-missile defence system to the region.

“This is about deterrence, not about war. We are not going for war,” the U.S. defense chief Shanahan told reporters.

“Our biggest focus at this point is to prevent Iranian miscalculation. We do not want the situation to escalate,” he added.

But lawmakers were divided, mostly along partisan lines, about the nature of the threat from Iran and whether the Trump administration’s response was making the situation better or worse.

Relations between Tehran and Washington have plummeted since last year when U.S. President Donald Trump pulled Washington out of a landmark 2015 nuclear deal between world powers and Iran that curbed Tehran’s nuclear program in exchange for relief from crippling economic sanctions.

House Armed Services Committee Chairman Adam Smith  said “There was a lot of talk at the briefing of the huge risk of Iran miscalculating and there is a risk of miscalculation on both sides, and that remains my biggest concern.”