Quizzed on whether higher borrowing costs were imminent, Belgian central bank chief Guy Quaden said in a newspaper interview it was not possible to answer given the large degree of uncertainty. He also said the ECB was uncomfortable with excessive exchange rate swings.
The remarks were less hawkish than fellow governing council members Axel Weber and Juergen Stark, who have suggested an ECB interest rate increase has been postponed rather than abandoned after it left borrowing costs on hold last week.
"Mr Quaden's comments perhaps go the furthest at hinting that the ECB might not raise rates further at all," said Julian Callow, chief European economist at Barclays Capital in London.
"They implicitly reinforce this conclusion were the euro to continue to move significantly higher (which seems quite likely under current circumstances), amid slowing U.S. demand expansion," he added.
A rate hike had been expected this month after ECB President Jean-Claude Trichet used the words "strong vigilance" following the bank's August monetary policy meeting, in the past a signal that higher rates are imminent.
He said last week he would use the phrase again when the time was right.
A slim majority of economists expect the ECB to tighten borrowing costs once more by December, a Reuters poll showed after Thursday's rate decision. The bank has hiked rates by a quarter-point eight times starting in December 2005.
"It is absolutely premature to say on the basis of our present knowledge," ECB Governing Council member Yves Mersch said on the outlook for rates as he presented a report by the Luxembourg central bank.
The ECB was ready to tighten borrowing costs if necessary "in a timely and decisive manner" but if the impact of the turbulence on credit markets proved protracted there was a higher risk of growth being hampered, he added.
Quaden told Thursday's edition of Belgian business daily L'Echo when asked whether the ECB would resume raising rates: "It is not possible to answer this question categorically given the big uncertainty there is currently."
"The scenario of the ECB remains valid, that is, slightly lower growth in 2007 than in 2006 but still close to the growth potential and with persistent inflationary tensions," he said.
"But it is true that the uncertainty which surrounds this scenario has strongly increased these last weeks."
Governing Council member Erkki Liikanen told reporters in Helsinki it would take months rather than weeks for markets to return to normal conditions and urged greater transparency.
"The faster the transparency increases on the market, the faster markets will normalise," he said.
Mersch said quarterly earnings reports from commercial banks would help shed light on the situation.
In its latest monthly bulletin, published on Thursday, the ECB said the global impact of the U.S. economic slowdown had so far been limited.
However, it said it was still unclear whether recent market turmoil would "lead to a lasting reappraisal of global financial market risks and a loss in confidence with possible implications for the real economy."
Callow at Barclays Capital said there had been a shift in the assessment of ECB staff compared with the August monthly bulletin, with the bank adopting a more moderate tone.
"In particular a month earlier the ECB staff were evidently much more concerned about inflationary risks, particularly from domestic demand and labour market tightness ... although food inflation has emerged as a new source of attention," he said.
"Nonetheless there is palpably a tone that is less sanguine about the economic outlook, especially evident in the international section."
The bulletin, as usual, repeated the Governing Council's statement from the previous monetary policy meeting.
In its analysis of economic and monetary developments, the ECB said risks to global expansion had recently increased due to the tensions in the U.S. mortgage market and there were fears of growing spillovers to other segments.
"Risks also relate to global imbalances, protectionist pressures and the possibility of further increases in oil and commodity prices," it said.