New Delhi, April 9 -- Semiofficial news agencies in Iran published a chart Thursday suggesting the country's paramilitary Revolutionary Guard put sea mines into the Strait of Hormuz during the war, in a message that may be intended to pressure the U.S. as uncertainty hangs over a days-old two-week ceasefire and further negotiations are set to begin in Pakistan.

The charts were released by the ISNA news agency, as well as Tasnim, which is believed to be close to the Guard, and showed a large circle marked "danger zone" in Farsi over the Traffic Separation Scheme, which was the route ships used to take through the strait, the narrow mouth of the Persian Gulf through which 20% of all oil and natural gas traded once passed.

The chart sugges...