* Devaluation ruled out in short term - source
* Belarus earlier widened OTC rouble trading band by 10 pct
* Rouble could weaken further - analysts
* Belarussians queue up to buy gas, underground rail tickets
(Adds cbank, FinMin statements, analyst comments)
By Andrei Makhovsky
MINSK, March 31 (Reuters) - Belarus has brought in a 20-30 day moratorium on changing foreign exchange regulations or devaluing the rouble, expecting to secure Russian financial aid by then, a banking source said on Thursday.
Analysts say a de facto 10 percent rouble
"Everybody is expecting a devaluation from April 1. This will not take place from April 1 nor in the following days," the source told Reuters, adding that the decision on a moratorium was made at a session of the central bank's board on Wednesday.
The source said this meant that over the 20-30 day period rules for operating in the internal market would not change.
"By that time we expect to get a loan (from Russia)," the source said.
The central bank later on Thursday issued a statement confirming it had no intention of introducing any additional foreign exchange controls.
"All the measures needed to preserve and increase gold and foreign currency reserves have been implemented by now," it said. However, the bank made no official pledges on exchange rate stability.
Separately, the Finance Ministry sought to reassure investors, including the holders of Belarus' two Eurobonds, saying servicing foreign debt was a priority.
FURTHER DEVALUATION MAY BE NEEDED
On Tuesday, the central bank effectively allowed the Belarussian rouble to devalue by 10 percent on the interbank market by widening the trading band for local banks.
The currency has come under pressure because of a big trade deficit and generous wage increases and loans handed out by the government in the run-up to last December's presidential election, when President Alexander Lukashenko secured a fourth term.
Analysts say that Tuesday's move could help Belarus secure bailout loans from powerful partners such as Russia but would not by itself fix an unsustainable foreign trade gap.
"Our estimates suggest that the fair (exchange) rate may stand within 3,500-4,000 roubles per dollar now," ING said in a note on Thursday.
The official rate is 3,045 roubles per dollar.
"Therefore, the recent central bank move may turn out to be not enough," ING said.
The central bank, whose forex reserves fell 20 percent in the first two months of this year to $4 billion due to the trade deficit, had prior to Tuesday's move allowed banks to deal at only 2 percent above or below the official rate.
Moscow has said it wanted to see a credible anti-crisis plan before extending loans to Belarus and analysts say the limited devaluation may have been part of it.
QUEUES FOR FUEL, RAIL TICKETS
However, the interbank market remains illiquid.
"There is barely any interbank market at all," said a trader at one Belarussian bank.
"Banks quote foreign currency 10 percent above the central bank rate but there is no excess foreign currency (that could be traded), it all goes towards meeting the demand of banks' own customers."
The "soft" devaluation, along with the absence of foreign currency cash at foreign exchange bureaux and planned increases in fuel and public transport prices, has prompted Belarussians to spend money on goods rather than keep the rouble.
Unusually long queues formed at gas stations this week ahead of a 10 percent price increase announced earlier.
Minsk residents were also queuing up to buy underground rail tickets ahead of a 20 percent price hike and the underground rail operator had to limit sales to two tickets per person.
Importers of consumer electronics and other durable goods say demand has risen as Belarussians expect prices to increase and foresee shortages.
"The situation could be described as a crisis," said a businessman who imports computers, speaking on condition of anonymity. "Large importers are afraid to import goods because they expect a devaluation and are unsure about pricing." (Writing by Richard Balmforth and Olzhas Auyezov; Editing by Susan Fenton)