Iran detained 15 British seamen in the Gulf March 23 for violating its maritime border with Iraq. Britain has insisted the servicemen were in Iraqi waters under a UN mandate, and were returning in dinghies to the HMS Cornwall after patrolling oil platforms.
"Any statements by the American side designed to support the British government can only further complicate the situation [around the U.K. sailors]," the ministry said. "The U.S. president had better refrain from ill-considered and unreasonable comments."
On Sunday, the U.S. president called their capture "inexcusable behavior," and urged Tehran to release the U.K. crew.
London froze official bilateral contacts, suspended the issuance of visas to Iranian officials and referred the case to the UN Security Council Wednesday.
The UN expressed "grave concern" over the sailors' capture.