LONDON - Commodities experienced a volatile week, as traders eyed the oil supply glut, the dollar and intensifying concerns that Greece could default and crash out from the eurozone.

The EU has called an emergency eurozone summit in Brussels for Monday, seeking to break the five-month deadlock between the anti-austerity government in Athens and its international creditors.

"Looking ahead to next week, the focus of attention will remain with Greece," said analyst Julian Jessop at research group Capital Economics.

"Unless there is a significant breakthrough in the emergency leaders' summit on Monday, which we deem unlikely, the prolonged uncertainty will continue to undermine commodity prices."

OIL: Crude oil prices weakened as the dollar, benefitting from Greek worries, rose against the euro.

"Prices danced to the tune of the dollar/euro exchange, which has been influenced by the latest Greek developments," said analysts at London-based oil brokerage PVM.

Greece insists a last-ditch deal on its debt is possible, but the European Central Bank held Friday an emergency meeting to increase its financial lifeline Greek lenders as fears grew of a run on Greek banks after a rush of deposit withdrawals.

The European single currency fell Friday to $1.1334. The stronger greenback makes dollar-denominated commodities like oil more expensive for buyers using weaker currencies.

That tends to cap demand and send prices lower.

However, on Thursday the euro had struck a one-month peak at $1.1436 in a jump driven by incorrect reports that Greece had won a delay in its debt payments.

Meanwhile the oil market rose Thursday as dealers reacted to the US Federal Reserve's decision the previous day to leave its key interest rate unchanged.

The world's most powerful central bank said it would adopt a cautious and methodical approach to raising them later in the year.

Elsewhere, investors remain concerned that top producer and de-facto OPEC cartel leader Saudi Arabia could boost output in an already over-supplied market, analysts said.

Investors have previously voiced concern over OPEC's strategy of maintaining high output levels to hurt US shale producers.

The resulting huge global supply glut has been attributed as the main cause for oil prices collapsing by more than 50 percent between June 2014 and January.

By Friday on London's Intercontinental Exchange, Brent North Sea crude for delivery in August slid to $62.66 a barrel from $64.35 a week earlier for the expired July contract.

On the New York Mercantile Exchange, West Texas Intermediate (WTI) or light sweet crude for July dipped to $59.40 a barrel from $59.99 a week earlier.

PRECIOUS METALS: Gold gained ground as dealers sought shelter from Greek default worries and mulled the cautious US interest rate outlook.

"Ahead of key events for Greece, the ultimate safe haven, gold, is finding some buyers," noted IG analyst Chris Beauchamp.

"Consolidation above $1,200 is a good first step if the metal is to attempt to regain the May highs, and a deterioration in the Greek situation should provide some modest upward force for the metal."

Gold is widely regarded by investors as a safe bet in times of economic uncertainty.

International creditors insist Athens must do more in return for the needed funding if it is to meet a debt repayment of around 1.5 billion euros to the International Monetary Fund on June 30.

"As the situation of Greece's payment to the IMF on June 30 remains in the limelight, volatility in gold price may be affected in the coming days," cautioned analyst Merav Brenner at options trading platform provider ORE.

By Friday on the London Bullion Market, the price of gold gained to $1,203.40 an ounce from $1,182.80 a week earlier.

Silver advanced to $16.12 an ounce from $15.93.

On the London Platinum and Palladium Market, platinum edged down to $1,085 an ounce from $1,095. Palladium fell to $718 an ounce from $739.

BASE METALS: Base or industrial metals prices mostly fell on Greek woes and Chinese demand concerns.

"The escalating crisis surrounding Greece's negotiations with its creditors and its potentially negative implications for the eurozone economy weighed on investor sentiment this week," said Jessop at Capital Economics.

"Industrial metals prices were particularly hard hit as Chinese economic data remained soft."

By Friday on the London Metal Exchange, copper for delivery in three months fell to $5,667.50 a tonne from $5,898.50 a week earlier.

Three-month aluminium reversed to $1,690.50 a tonne from $1,748.50.

Three-month lead slid to $1,792 a tonne from $1,852.50.

Three-month tin rose to $15,210 a tonne from $14,940.

Three-month nickel edged down to $12,620 a tonne from $13,035.

Three-month zinc dipped to $2,052 a tonne from $2,112.50.

COCOA: Prices rose once more on the back of tight supply worries, in a mixed trading week for soft or agricultural commodities.

"Agricultural commodity prices have had mixed fortunes since mid-May, with roughly half seeing rises and half seeing falls," said analyst Hamish Smith at Capital Economics.

"While concerns about supply constraints have helped support cocoa and robusta prices, the opposite is true for sugar which continues to be weighed down by huge global supplies."

By Friday on LIFFE, London's futures exchange, cocoa for delivery in September climbed at £2,155 a tonne, from £2,094 for the July contract the previous week.

On the ICE Futures US exchange, cocoa for September rose to $3,296 a tonne from $3,109 for the July contract the previous week.

SUGAR: The market dived in New York to 11.61 US cents per pound, hitting the lowest level for six and a half years on abundant supplies.

"Supply continues to be plentiful in the short and medium term," agreed Sucden brokers analyst Nick Penney.

By Friday on LIFFE, a tonne of white sugar for delivery in August dipped to $346.30 from $346.80 a week earlier.

On ICE Futures US, unrefined sugar for October was unchanged at 11.67 US cents from a week earlier for the July contract.

COFFEE: Prices rebounded from the previous week's losses.

"The recent surge (in prices) has been sparked by fears of short-term supply constraints amid hoarding by Vietnamese coffee producers," said analyst Jessop.

On ICE Futures US, Arabica for delivery in September rose to 131.90 US cents a pound from 131.60 cents a week earlier.

On LIFFE, Robusta for September increased to $1,784 a tonne from $1,711.

RUBBER: Prices declined on a demand slowdown, particularly in key market China, traders said.

On Friday, the Malaysian Rubber Board's benchmark SMR20 fell to 158.95 US cents a kilo from 162.90 cents a week ago.