KABUL, Afghanistan — Iran’s decision to stop up to 2,500 fuel trucks at its border with Afghanistan is tantamount to an “embargo,” an Afghan commerce official said today, as others warned the move could leave millions of Afghans shivering as winter rolls in.

The unofficial ban, now in its second week, has pushed up wholesale domestic fuel prices as much as 70 percent. The shortage of fuel also threatens to stop trucks loaded with commercial goods from reaching the capital along a key southern transport route.

Iran today acknowledged a link between the ban and its recent decision to slash domestic fuel subsidies in a bid to cut costs and boost an economy squeezed by international sanctions. Afghan officials say Iran has also told them it is concerned the shipments are destined for NATO forces in Afghanistan, though Afghan and NATO officials deny that.

Iran “wants to impose a kind of sanction or embargo on us,” said Farid Shirzai, head of the Afghan Commerce Ministry’s fuel department.

Iran supplies about 30 percent of the country’s refined fuel. The remainder of the blocked shipments of vehicle and heating fuel comes from Iraq and Turkmenistan and is only transiting Iran.