ISTANBUL, Jan 4 (Reuters) - Turkish refiner Tupras has asked the country's statistics agency to stop publishing details of its oil imports from Iran as it comes under pressure over tightening U.S. sanctions on Tehran's oil trade, Turkish officials said on Friday.
The Turkish Statistical Institute (TUIK) stopped publishing the origin of Turkey's crude oil imports in late December, releasing figures for total monthly imports only, according to data on its website.
"Tupras asked TUIK not to release Tupras' oil import data from Iran, and TUIK stopped releasing the data," a Turkish official told Reuters, asking not to be named.
A second source familiar with the matter also said Tupras had made the request because it was coming under pressure over its imports from Iran.
Tupras officials could not be reached immediately while TUIK declined to comment.
The U.S. Senate in November approved expanded sanctions on global trade with Iran's energy and shipping sectors as it continued to ratchet up economic pressure on Tehran over its disputed nuclear programme.
The package kept in place exemptions for countries including Turkey that have made significant cuts to their purchases of Iranian crude, but new sanctions are due to take effect in February and U.S. lawmakers are preparing further measures.
Washington says Tehran is enriching uranium to levels that could be used in nuclear weapons and that its energy sales provide it with a financial lifeline. Iran says its nuclear programme is for peaceful purposes.
Turkey cut its Iranian oil purchases by at least 20 percent last year in order to win its exemption from the sanctions.
But Turkish officials say they have repeatedly made clear to Washington how dependent Turkey is on imported energy, having once sourced more than 60 percent of its crude from Iran.
Trade data showed Turkey's crude oil imports from Iran fell by more than 30 percent to 75,281 barrels per day (bpd) in October from September while volumes of oil from other suppliers including Iraq and Saudi Arabia increased.
The latest figures on the TUIK website show only that total imports were 1.8 million tonnes for November.
Oil shipments by Iran more than halved in 2012 due to U.S. and European sanctions, straining Tehran's finances, pressuring its currency and igniting inflation.
(Reporting by Orhan Coskun and Humeyra Pamuk; Writing by Nick Tattersall; editing by Jason Neely)