The push for tighter sanctions on Iranian oil exports comes at a time when oil prices are already high. Last year was a record-shattering year for oil prices, which averaged $107 a barrel, about 14 percent more than in the previous record year of 2008, according to figures from the Organization of Petroleum Exporting Countries.

The U.S. oil import bill — for crude and refined products — jumped about $125 billion from 2010 to 2011.

Rising oil prices could hurt the fragile global economy, which includes economists’ other big worry: Europe.

Barclays Capital analysts noted on Friday that in terms of the euro currency, oil prices “have now almost matched their previous peak of July 2008,” draining money from economies already struggling with the sovereign debt crisis. Three of Europe’s most troubled economies — Greece, Spain and Italy — are also the E.U.’s biggest importers of Iranian crude and would be most affected by a new ban. (The United States already bars imports of Iranian crude oil.)

“At current prices, the world economy is going to grow at 3 percent to 3.5 percent this year,” said Adam Sieminski, chief energy economist at Deutsche Bank. “That’s not great, but okay. At $125 a barrel, it is only going to grow 2.5 percent, and that’s not very good. And at $150, we might only grow 1 percent, and that’s a disaster.”

Many analysts do not think Iran would risk military conflict by carrying out its threat to close the Strait of Hormuz, used by tankers carrying 17 million barrels of oil a day, about a fifth of the world’s consumption. E.U. leaders meet Jan. 23 to decide whether to embargo Iranian crude, but oil prices fell Friday on reports that any import ban would be phased in or delayed six months.

Within that time, a new overland pipeline from the United Arab Emirates would open and Libyan output, damaged by civil war, would probably return to normal. And European refiners, who buy about 600,000 barrels of Iranian oil daily, could line up new suppliers.

Moreover, that delay would give Iran yet another chance to negotiate international inspections of its nuclear program. “That’s the end game,” said Julian Lee, an energy expert at the London-based Center for Global Energy Studies, “to get the Iranians to sit at the table and talk and put in proper monitoring of their nuclear industry. The sanctions aren’t an end in and of themselves.”

Meanwhile, U.S. and European efforts to put a crimp in Iran’s exports appear to be having an effect already.

U.S. restrictions on doing business with Iran’s central bank have been felt in India, the second-largest buyer of Iranian oil. Refiners there are seeking new suppliers after India’s government threatened not to sign a waiver to protect them from U.S. sanctions, according to Lloyd’s List. In addition, Lloyd’s List said, since Iran’s threat to close the Strait of Hormuz, Turkish banks used by Indian refiners to pay for Iranian crude are refusing to transfer those funds.