* U.S. oil falls more than $1 as copper tumbles to 4-year lows
U.S. crude stocks seen up 2.2 mln barrels last week - poll
* France says sanctions on Russia could come this week
(Updates trading, dateline, byline, previous LONDON, adds analyst comment)
By Elizabeth Dilts
NEW YORK, March 11 (Reuters) - U.S. crude oil fell on Tuesday to below $100 per barrel for the first time in a month as the potential for more Chinese corporate bond defaults and rising crude stocks in the United States raised concerns about the growth of oil demand.
Oil fell more than $1 after copper prices dropped to four-year lows on worries that other firms may follow loss-making Shanghai Chaori Solar Energy Science and Technology Co Ltd, which defaulted last week.
Meanwhile, data from the U.S. government on Wednesday was expected to show another large build in domestic crude oil inventories at a time of low demand as U.S. refiners have cut utilization rates to get ready for the summer driving season.
Brent oil futures rose slightly on Tuesday, supported by tensions over Ukraine as the European Union and United States prepared sanctions against Russia that could come soon.
The French foreign minister said sanctions against Russia could come as early as this week, and Poland's prime minister said the European Union would issue sanctions on Monday.
Russian oil exports from its key Baltic Sea ports remain uninterrupted, but traders were watching statements from Russia closely.
"The worries that you could see a supply disruption from Russia is making some sellers - who would otherwise be inclined to sell off because of increasing stockpiles and weak fuel demand (in the U.S.) - hold on," Gene McGillian, an analyst at Tradition Energy in Stamford, Connecticut.
Brent futures traded 23 cents higher at $108.31 a barrel by 1:29 p.m. EST (1729 GMT). U.S. crude fell $1.01 to $100.11 a barrel.
Brent's premium over U.S. crude <CL-LCO1=R> has widened in recent days after contracting to $5.44 on March 5, its tightest point in almost five months. It last traded at $7.96 a barrel.
Aside from the crisis in Ukraine, Brent was supported by escalating tensions over Libya's crude exports.
Libya's parliament voted Prime Minister Ali Zeidan out of office on Tuesday after a tanker loaded with oil from a rebel-held port escaped the navy, officials said. The Libyan navy opened fire on the tanker, damaging the vessel, a Libyan military spokesman said.
Meanwhile, state oil officials said Libya's El Sharara oilfield increased production to around 200,000 barrels a day, up from 150,000 bpd on Monday, but analysts said output remained uncertain in the long term.
Indicating a weak demand outlook, U.S. crude inventories are expected to have risen by 2.2 million barrels on average last week as a bitter cold spell ends and as refiners take down plants for scheduled maintenance.
That forecast follows recent data from China that showed a sharp drop in exports, pointing to weak economic activity.
The U.S. Energy Information Administration (EIA) cut its forecast for 2014 world oil demand growth by 40,000 bpd in its monthly Short Term Energy Outlook on Tuesday. It predicted a 1.22 million barrel year-on-year increase.
Traders were looking ahead to the release of weekly inventory data from the American Petroleum Institute later on Tuesday and official data from the EIA on Wednesday.
(Additional reporting by Ron Bousso in London and Manash Goswami in Singapore; Editing by Anthony Barker, Jason Neely and Bernadette Baum)