The United States has vowed to blockade Iran's ships until the country makes a deal to end their war. But is the blockade working?

Analysts and ship-tracking data paint a complicated picture. Shifting objectives and shadowy activity by vessels making the success of the US operation hard to measure.

"There's been confusion over the scope and the parameters of the blockade because of conflicting information given by the US administration and some delays in when information has been released," Bridget Diakun, an analyst at shipping journal Lloyd's List Intelligence, told AFP.