Her comments follow a report by the Interfax news agency which quoted a Belarus oil industry source as saying that Belarus's refineries were not receiving Russian oil on Monday morning.

Russian officials also denied the report, which had prompted fears of a repeat of a 2007 energy crisis that saw a cut in Russian oil supplies to the EU for several days.

Price rise

Oil has flirted with the $80 level the last two trading days after jumping from $69 a barrel last month.

The US economy has show signs of improvement, with the unemployment rate falling to 10 per cent in November last year from 10.2 per cent in October.

The government is scheduled to announced December's results later this week.

"Most people expect the economy to get better this year, and demand should follow," said Victor Shum, an analyst with consultancy Purvin & Gertz in Singapore.

"But traders so far lack the conviction to trade oil above $80 for long simply because of there haven't been clear indications of growing demand yet."

Colder weather has also lifted crude prices recently by boosting demand for heating oil, Shum said.

Monday was the first day of trading as Friday was a New Year holiday.