Oil prices ticked lower but held firm near 10-month highs on Tuesday after a general strike threat by Nigerian unions and further violence in the delta helped extend the market's gains to a fourth session. London benchmark Brent crude edged 10 cents lower to $72.08 a barrel after touching intra-day peak of $72.25 on Monday, its highest since August 28.
US light sweet crude eased 16 cents to $68.93 a barrel, paring only a fraction of Monday's $1.09 rise, the fourth day of a rally that has lifted prices by nearly $4. "At the moment it's all about what's happening in Nigeria, the potential for a real strike there is helping prices up," said Andrew Harrington, industry analyst from ANZ Bank in Australia.
Nigeria moved into the market's spotlight on Monday after unions said they would start an indefinite general strike from Wednesday. They said the action would include the oil sector, although it was unclear how quickly production would be affected. Late on Monday the government offered a series of concessions, including halving a recent fuel price increase and reverting the value-added tax, a presidency source said.
Senior union officials at the talks declined to comment, but one said the offer was insufficient. The two sides may resume talks on Tuesday, he added. Armed militants also stormed two Western oil facilities in the remote delta, cutting a further 82,000 barrels per day (bpd) of output from the world's eighth-largest exporter and taking the country's total shut-in production to some 756,000 bpd.
Prices began rising in the middle of last week, after US weekly oil inventory data showed flat gasoline stocks and a further fall in heating oil supplies, raising fears that the nation's strained refiners would struggle to meet demand.
Analysts expect a gasoline and distillate stock to have risen over last week as refinery operations recover from unseasonably low level, according to a preliminary poll.
Crude stocks were seen marginally higher. Oil traders are also sizing up the medium-term outlook for the market, with conflicting signals from consumer nations represented by the International Energy Agency which says oil stocks may fall precariously low without more Opec crude and the producer cartel itself, which says supplies are sufficient.
Violence in the Gaza Strip has also rattled traders, although analysts said there was little indication of the power struggle spilling over to neighbouring oil-producing countries. US crude hit a record high of $78.40 a barrel nearly a year ago on fears that fighting between Israel and Lebanese Hezbollah guerrillas could spread to Middle East oil producers.