US Defense Secretary Mark Esper says it will take more time to form a coalition of nations to protect merchant vessels around the Strait of Hormuz.
Esper told reporters in London on Thursday that countries are in different phases of their processes for participating in the US initiative.
He said some governments require approval of their legislatures, and that the process takes time.
So far, three countries -- Britain, Bahrain and Australia -- have announced that they will join the initiative. Many countries are hesitant to join, apparently out of consideration for their relationship with Iran.
Esper stressed the importance of enlisting as many countries as possible to carry out various duties.
The United States hopes the US-led security mission, as well as economic sanctions, will step up pressure on Iran.
Tehran announced on Wednesday that it will start developing new centrifuges for uranium enrichment. The move takes the country a step further from its commitments under the 2015 nuclear deal.
NHK
