The U.S. Navy is imposing a sea blockade against Iran — the latest escalation in the war that has seen the flow of key energy supplies choked off at the Strait of Hormuz.

The White House says it wants to choke off Iran's oil export revenue. But experts say that blockades are often unpredictable ...

Measles vaccinations have saved nearly 20 million lives in Africa since the year 2000 and more than 500 million children were protected through routine immunisation, but the continent remains offtrack ...