Any blockade of the strategic Strait of Hormuz by Iran would send oil prices soaring by more than $30 a barrel, the IMF said in a report released Wednesday.

The International Monetary Fund made the warning last week in a document prepared for a meeting of G-20 deputy finance ministers in Mexico, naming it as a key risk for the already shaky global economy as the West jacks up pressure on Tehran over its suspect nuclear program.

The Fund said that a somewhat broad embargo on Iranian oil, effectively taking 1.5 million barrels a day of Iran's exports off the global market without another producer compensating for it, risked pushing the market price for oil up 20-30 percent, "about $20-30 a barrel currently."

"A Strait of Hormuz closure could trigger a much larger price spike, including by limiting offsetting supplies from other producers in the region," the report said.

Iran has threatened several times in recent months that if Europe, the United States and their allies try to shut down the country's oil exports, it would close the narrow Hormuz strait.

The waterway which links the oil-rich Gulf with the Arabian Sea and beyond is crucial to the global economy, as about 40 percent of global oil exports pass through it.

Pressure grew this week on Tehran after the European Union agreed to halt imports of Iranian crude, closing off an outlet for about 600,000 barrels a day.

Saudi Arabia has stepped up production to compensate for that loss, and could match more market shortfalls if pressure on other countries like China and India to stop buying Iran's oil is successful.

But, the IMF warned, the Saudi buffer is also at risk with a Hormuz closure.

"A blockade of the Strait of Hormuz would constitute, and be perceived by markets to presage sharply heightened global geopolitical tension involving a much larger and unprecedented disruption.

"A blockade would also neutralize a large part of current OPEC spare capacity. Alternative routes exist, but only for a tiny fraction of the amounts shipped through the Strait, and they may take some time to operationalize while transportation costs would rise significantly."