Iran's parliament is set to vote on whether to stop sending oil to the European Union, its second-biggest customer.
The proposal is a response to an EU vote last week to impose an oil embargo against Iran and freeze the assets of its central bank over its nuclear program.
It is presumably aimed at denying shakier European economies the six-month transition period envisaged by the EU for finding alternative sources and delivering a blow to countries that have prepaid for Iranian oil but might find buyback terms difficult under fresh economic sanctions targeting Tehran.
The EU ban on Iranian oil purchases does not take effect until July -- only after Iran finishes deliveries to European countries like Greece and Italy where some oil shipments have already been paid for.
The United States has approved -- but has yet to implement -- new sanctions targeting Iran's central bank, a move seen as further impeding Tehran's ability to sell oil.
German Foreign Minister Guido Westerwelle warned in the hours ahead of the planned Iranian vote that the EU would not allow Iran to push it into a corner with the tactic.
Westerwelle called the threat "a regrettable and dangerous escalation in rhetoric," saying the EU would find ways "to compensate for delivery stoppages."
If Iran's parliament passes the bill to stop oil shipments to Europe, the legislation still must be approved by the Guardians Council to become law.
If that happens, some EU states relying on Iranian oil -- namely Greece and Italy -- could face hardships.
But in the long run, analysts see Arab producers satisfying some of the shortfall.
compiled from agency reports