PRECIOUS-Gold climbs towards 6-yr peak on dovish central banks, Iran tensions

* SPDR posts biggest one-day percentage gain since 2008

* Speculators increase net longs in COMEX gold

* Spot gold prices up nearly 8% so far this month (Updates prices)

June 24 (Reuters) - Gold climbed on Monday towards the near six-year high reached in the previous session, driven by dovish signals from global central banks and increased tensions between the United States and Iran.

Spot gold was up 0.5% at $1,405 an ounce by 1240 GMT, heading for a fifth straight session of gains. Gold prices hit $1,410.78 on Friday, their highest since Sept. 4, 2013.

U.S. gold futures rose 0.7% to $1,410 an ounce.

“The weakness of the U.S. dollar, gold’s technical picture and interest from investors themselves have become self-sustaining factors, especially after the massive inflows into gold exchange-traded funds,” Commerzbank analyst Eugen Weinberg said.

Tensions between the United States and Iran also supported gold, he added.

Holdings of the world’s largest gold-backed ETF, SPDR Gold Trust, rose 4.6% on Friday from a day earlier, its biggest one-day percentage gain since September 2008.

The U.S. Federal Reserve and the European Central Bank last week hinted that they were open to easing policy to counter a global economic slowdown, exacerbated by global trade tensions.

Helping gold’s appeal, the dollar fell to a three-month low against a basket of currencies on bets the U.S. central bank would start lowering interest rates as early as next month.

Meanwhile, U.S. President Donald Trump said on Sunday he was not seeking war with Tehran, but tensions remain high between the longtime foes, with Washington due to announce “significant” sanctions on Iran on Monday.

Gold prices have risen nearly 8% so far this month, and more than $70 just over the past week.

Hedge funds and money managers boosted their bullish stance in COMEX gold in the week to June 18 and speculators switched to a net long in silver futures and options, the U.S. Commodity Futures Trading Commission said on Friday.

Gold holding above the psychologically important $1,400 level is a positive signal for consolidation after last week’s rally, said Carlo Alberto De Casa, chief analyst at ActivTrades.

“The gold rally pushed silver up too, but the scenario in this case is less strong, as prices keep bouncing on the resistance area at $15.50,” he said.

Silver edged 0.3% lower to $15.31 per ounce and platinum was up 0.5% at $813.68.

Palladium rose 1.2% to $1,517.23 an ounce.

The market’s focus now shifts to whether Washington and Beijing can resolve their trade dispute at a summit in Japan this week of leaders from the Group of 20 leading world economies. (Reporting by Nallur Sethuraman and Eileen Soreng in Bengaluru; Editing by Louise Heavens/Jan Harvey/Jane Merriman)