* New frontmonth Feb rises towards $43 on weaker U.S. dollar
* Saudi Arabia, Kuwait try to scotch doubts on OPEC curbs
* Gunmen attack vessels in Nigeria, Russians kidnapped (Updates prices, adds details)
By Fayen Wong
PERTH, Dec 22 (Reuters) - Oil rose to near $43 a barrel on Monday, helped by tough talk from top OPEC producers of compliance with their record output cut and a weaker U.S. dollar, while U.S. data showed speculators betting on a bounce.
But analysts said the rebound, which came after prices dropped to a four-year low of $33.87 on Friday, was expected to be short-lived as downside risks continued to lurk.
U.S. light crude for delivery in February <CLc1>, when cuts in OPEC production were expected to take hold, rose 54 cents to $42.90 a barrel by 0800 GMT, after climbing to as high as $43.44 earlier.
The January crude contract expired on Friday, when it traded at a deep discount to February, as key mid-continent storage tanks filled to near overflowing.
London Brent crude <LCOc1> gained 40 cents to $44.40.
"Prices are on a rebound after the sharp falls last week. A weaker U.S. dollar and OPEC (talks) are also influencing prices," said Ryuichi Sato, an analyst at Mizuho Corporate Bank in Tokyo.
"But we think this rebound is temporary because there is still a lot of downside risks on the economic front and market sentiment remains very bearish."
A surge in net speculative investment in the crude complex to its highest since mid-May, as of Dec. 16 data, also fed the emerging view that markets may have hit bottom for now, although fears over the outlook for demand tempered hopes for a bounce.
Speculators increased their net length to 64,120 lots during the week to last Tuesday, a surge from 10,807 the previous week, Commodity Futures Trading Commission data showed. [
]The U.S. dollar fell against the euro on Monday, giving up some of its gains made after the U.S. government offered a lifeline to U.S. carmakers, as investors remained concerned over the deepening economic recession. [
]Oil prices have fallen more than $100 from their peak of above $147 in July as the global economic crisis slashes oil demand.
Pledges by OPEC last week to cut output by 2.2 million barrels per day (bpd) -- its deepest ever supply cut -- have failed to stem the slide in January oil prices, which expired on Friday at $33.87 a barrel, the lowest since February 2004.
OPEC kingpin Saudi Arabia moved to scotch doubts on Sunday on the cartel's pledge to cut oil production to stabilise world oil markets, while Kuwait's oil minister said separately on Sunday he was confident that OPEC members will comply with latest output cuts decided by the group. [
]"Don't doubt the efforts of OPEC or its members to return the oil market to stability," Saudi Arabia's Ali al-Naimi told reporters. [
].But Asian refiners, many of which had expected at least some of OPEC's biggest producers to make deeper visible cuts in January oil shipment schedules over the weekend, have yet to receive notice from OPEC's core Gulf members of any further reductions to oil supplies since the group announced cuts last week. [
]In OPEC-member Nigeria, where production has been hindered for years by repeated militant attacks, gunmen in speedboats attacked three oil services ships and kidnapped at least two Russians in separate incidents in the Niger Delta, sources said on Saturday. [
]Global spending on oil/gas exploration and production will shrink 12 percent to $400 billion in 2009 as the steep slide in energy prices and tight credit markets reverse a six-year trend of rising budget, analysts at Barclays Capital said. (Editing by Ramthan Hussain)