European countries on Monday demanded to know more about U.S. President Donald Trump's plans for the war on Iran and when the conflict might end as they weighed whether to agree to his call to send warships to help shore up security in the Persian Gulf.

Trump has asked allies — including France, China, Japan, South Korea and Britain — to help secure the strait for global shipping. He said the U.S. was talking to "about seven" countries for military support to help reopen the trade route. But he wouldn't say which ones and gave no indication of when such a coalition might be formed.