The US says it wants to create an multinational military coalition to safeguard waters around Iran and Yemen.
Gen Joseph Dunford, chairman of the US military's Joint Chiefs of Staff, said he wanted to "ensure freedom of navigation" in the region, which provides essential trade routes.
The US has blamed Iran for attacks on six oil tankers in May and June.
Gen Dunford said the US was talking to a number of countries with the "political will" to support the plans.
The US would provide "command and control" ships, leading surveillance efforts, he said. However, the aim would be for other countries to offer boats to establish patrols nearby, and escort commercial ships carrying their flags through the area.
Gen Dunford said the US would "work directly with the militaries to identify the specific capabilities" each country has to support the initiative.
The straits of Hormuz and Bab al-Mandab are strategically important locations, providing access from the Indian Ocean to the Gulf and the Red Sea respectively.
About a fifth of oil that is consumed globally passes through the Strait of Hormuz, which connects the Indian Ocean with the Gulf, while oil tankers heading from the the Middle East to Europe via the Red Sea pass must through Bab al-Mandab.
