* Currency witnesses steep 20 percent drop in less than one month
* Central Bank plans to inject $100 mln to prop up pound - bankers
* Bank orders traders to sell dollars below black market price
By Suleiman Al-Khalidi
AMMAN, May 11 (Reuters) - Damascus has announced measures to halt the fall of Syria's currency, but traders expressed doubt it would work after the unravelling of a ceasefire and the collapse of peace talks brought one of the fastest falls of the five year civil war.
The pound has lost more than 90 percent of its value over the course of five years of fighting, and the fall accelerated in recent weeks since peace talks broke up in Geneva and fighting resumed in Aleppo between rebels and government forces.
The currency, worth 47 to the dollar on the eve of the civil war, now trades at around 635 to the dollar in Damascus and even higher rates in other cities, having fallen by 20 percent in less than a month, according to dealers reached by telephone.
Many Syrians have all but given up on the pound and use dollars for day to day transactions, hoarding hard currency to protect their savings.
Central Bank Governor Adeeb Mayaleh said on Wednesday he would do what it takes to halt the fall. The bank had injected $10 million into the market so far this week, he said.
"The rise in the dollar's exchange rate is not at all justified in light of the Central Bank's knowledge of the demand for foreign exchange and supply and the extent of liquidity in Syrian pounds," Mayaleh told state media.
"The dollar's exchange rate will see a big drop as the measures take effect and speculators will suffer big losses," he said on Wednesday. He also met with currency traders to discuss the plans.
One senior financier in Damascus said the $10 million injection announced by Mayaleh so far was far too little to have an impact on exchange rates.
"If these measures are not accompanied by other broader steps to restore confidence we will see the pound hit the 700 benchmark against the dollar before June," the financier told Reuters.
Two financial sources in the Syrian capital, who are not officials but are familiar with government policy, said they understood the bank was planning to spend $100 million supporting the currency in coming days.
The bank aims to put the additional hard currency into circulation by ordering each licensed currency exchange firm to sell up to $1 million in dollars to the public at a rate of 620 pounds to the dollar. That would move the official rate closer to the black market rate in a bid to drive black marketeers out of business.