CHRONOLOGY - Standoff between Britain and Iran over sailors

(Reuters) - Iran seized 15 British Royal Navy sailors and marines a week ago while on a U.N. mission in the northern Gulf. Here is a chronology of the main events:

March 23 - Iran seizes 15 Royal Navy sailors and marines. British and Iranian envoys summoned to respective foreign ministries. Britain says personnel were in Iraqi waters, Iran says they had entered its territory.

March 24 - Iran says sailors have confessed to entering Iranian waters illegally. Britain denies this and repeats calls for their immediate release.

March 25 - Iranian and British foreign ministers speak by phone. British Prime Minister Tony Blair calls for sailors' release, insists they were in Iraqi territory. Iran says it may charge sailors for illegal entry.

March 26 - Iran tells Britain sailors are "fit and well" but does not disclose where they are being held.

March 27 - Blair warns of "different phase" if sailors not released. Britain shows Iran data which it says shows sailors were in Iraqi waters.

March 28 - Britain publishes global positioning coordinates showing sailors in Iraqi waters. Britain freezes diplomatic business with Iran, except for contacts over sailors.

Iran shows footage of captured sailors, publishes letter purportedly from woman sailor saying they had entered Iranian territory. British ministers outraged by video and letter.

March 29 - Britain says not seeking confrontation with Iran. Tehran suspends release of woman Faye Turney. United Nations issues statement expressing "grave concern". Britain had called for a stronger statement. Iran publishes second Turney letter.

March 30 - EU ministers consider measures to support Britain. Iranian televisions showed footage of a British marine confessing to entering Iranian waters.