By Jonathan Saul
LONDON, June 23 (Reuters) - An evacuation plan to enable hundreds of ships with some 11,000 seafarers stranded in the Gulf to sail through the Strait of Hormuz is underway after Iran and the U.S. reached a ceasefire deal, the United Nations' shipping agency said on Tuesday.
"We have now started contacting the ships to start the evacuation," a spokesperson with the U.N.'s International Maritime Organization (IMO) said, without providing a timeframe.
The IMO said it had secured the necessary safety guarantees and verified conditions for safe navigation.
"This large-scale operation will be carried out in close cooperation with Iran, Oman, all other coastal states in the region, the United States and the maritime industry," IMO Secretary-General Arsenio Dominguez said in a statement.
The evacuation process under the IMO plan, which has been under discussion for months, will be phased, Oman's defence ministry said separately in an advisory.
"Given the elevated risk of collision in the current environment, a gradual and controlled evacuation of vessel traffic is required," it said.
The Omani ministry said the so-called Traffic Separation Scheme was "not safe for use at this time" and two temporary routes to north and south of the scheme could be used for evacuation.
"Vessels will be contacted individually and advised of their allocated transit day by the parties coordinated by IMO," the ministry advisory said.
The scheme, adopted by the IMO in 1968, established routing lanes through Iranian and Omani waters in the strait.
Floating mines are among the major risks with waters around Hormuz.
(Reporting by Jonathan SaulEditing by Gareth Jones and Andrew Cawthorne)
