FRANKFURT, Germany (AP) -- The European Central Bank injected another $10.5 billion into money markets on Tuesday and said conditions were normalizing after several days of volatility.

European stock indexes fell after posting sharp gains a day earlier.

The 7.7 billion-euro offer from the ECB -- much smaller than cash infusions during the previous three trading days -- brought the total amount lent since Thursday to 211 billion euros ($288 billion). Major central banks around the world have also provided extra funds, but on a smaller scale.

"I call on all parties to keep their composure," ECB President Jean-Claude Trichet said, after what he called a "period of market nervousness."

"This attitude has been welcome and effective in recent days. It will help to consolidate a smooth return to a normal assessment of risks in liquid markets."

He also reiterated that conditions were close to normal.

"We are now seeing money market conditions that have gone progressively back to normal," Trichet said in the statement, itself a rare occurrence.

Fears about a credit crunch came after defaults on subprime loans, or those made to people with poor credit, climbed sharply in the United States in recent months and triggered concern about the impact on markets worldwide.

With cash reserves running low, banks refused to lend to each other and interest rates that banks charge each other rose well above the 4 percent level set by the ECB.

The ECB said it received 41 bids worth a total 45.96 billion euros ($62.74 billion) in the one-day offer Tuesday, a sign that demand remained strong. It also said it had allotted another 310 billion euros ($424 billion) as part of its normal weekly market refinancing operations.

Whether the efforts will have a lasting effect remains to be seen, said Celent analyst Cubillas Ding.

"At one level, it's a matter of confidence -- and here, the ECB and other central banking authorities in Japan and, to a certain extent, Asia as a whole -- are putting a stake in the ground with the intention of restoring confidence, or at the very least to set things going in that direction," he said. "I expect this to be a gradual process."

Andrew Wilkinson of Interactive Brokers said the ECB moved when it did because cash grew tight and many banks became more stringent about whom they would lend to.

"I don't think there was any initiative to set a precedent here. There was no nudge to the Fed nor any race to the tape here," he said. "The European time zone dictated that they were in the vanguard."

European indexes fell as Wall Street opened narrowly mixed as well after a drop in the U.S. trade deficit and a tame core inflation report helped investors absorb weaker-than-expected quarterly results from Wal-Mart Stores Inc., the world's largest retailer.

The U.K.'s FTSE 100 Index edged down 0.02 percent to 6,217.70 points, France's CAC-40 dropped 0.8 percent to 5,527.12, while Germany's DAX Index declined 0.2 percent to 7,462.28.