CENTCOM commander Adm. Brad Cooper says a blockade of Iranian ports "has been fully implemented," as the U.S.-Iran impasse over control of the Strait of Hormuz continues amid a delicate ceasefire.

The U.S. blockade of the Strait of Hormuz appeared to be working on Wednesday, as marine trackers reported no Iran-linked ships entering or exiting the strait since the blockade began on Monday.

Iran's Fars News Agency says a supertanker sailed through international waters and the Strait of Hormuz with its tracking system switched on, "without any concealment."

The U.S. Navy is blockading Iran. It is not blocking the Strait of Hormuz. Five things you need to know about how the blockade works and what happens next.

By Florence Tan, Mariko Katsumura and Jonathan Saul SINGAPORE/LONDON, April 14 (Reuters) - The first full day of a U.S. blockade on vessels calling at Iranian ports made little difference to Strait of Hormuz traffic on Tuesday,

The move sets off a high-stakes war of attrition that will test who has the higher threshold for pain—Tehran or global markets.

It is a high-stakes moment ahead of a closely watched summit between President Trump and Chinese President Xi Jinping in Beijing next month.