BERLIN—Shares in Deutsche Bank AG ended a volatile day unchanged, dragged down by lingering concerns about its health and noncommittal comments on possible state aid from German Chancellor Angela Merkel, and then pushed up by comments from a top Justice Department official that investors interpreted as positive news about a looming fine.

The bank's shares ended Tuesday at €10.55 ($11.82) in Frankfurt, the same level they reached on Monday after a decline of more than 7% to their lowest price in decades. During Tuesday's session, shares had been down as much as 3%.

The concerns—voiced by a number of analysts and investors—center on whether Deutsche Bank needs to raise capital to fortify its thin cushion to guard against losses and meet regulatory requirements. Such fears have intensified in the nearly two weeks since The Wall Street Journal reported that the U.S. Justice Department proposed the bank pay a $14 billion legal settlement to close out mortgage-securities probes.

Deutsche Bank said it didn't intend to pay "anywhere near" that amount and that negotiations were just starting. On Tuesday, a top Justice Department official, Bill Baer, speaking at a conference, discussed in general how banks who cooperate during mortgage-securities investigations could get credit for their assistance. He didn't mention Deutsche Bank by name, but investors appeared to interpret it as positive news for the bank and pushed shares up.

But Mr. Baer also sounded a critical tone about what he said was the failure by most banks to cooperate in the mortgage-securities probes. He said many banks have exaggerated their cooperation when in reality they've dragged out investigations, driving up their settlement costs unnecessarily.

To get credit for "productive self-disclosure," Mr. Baer said, banks must disclose facts about individuals no matter how senior they are, and must do so proactively.

The mounting worries about Deutsche Bank threaten to put the German government, which has railed against taxpayer-financed banking rescues in other European countries, in a tricky position.

Deutsche Bank of Monday publicly denied it had sought help from the German government and dismissed questions about its capital adequacy as speculation. On Tuesday Ms. Merkel sought to keep a low profile on the public debate about possible help for the bank.

"Deutsche Bank is one part of the German banking and financial sector, and of course we wish all companies, even when they are experiencing temporarily difficulties, to perform well," Ms. Merkel told reporters. "Apart from this, I don't want to comment."

Her remarks came after she was asked whether she believes that the government should come to the rescue of the bank following a sharp drop in Deutsche Bank's share price and other recent developments.

A German magazine over the weekend reported that Ms. Merkel had ruled out providing government assistance to Deutsche Bank before Germany holds national elections next September. The report, citing unnamed government officials, led a spokesman for Ms. Merkel to tell reporters on Monday that there was "no need for such speculation" about state aid for Deutsche Bank.

The report in Focus magazine nonetheless was seen as contributing to Monday's selloff in shares of Deutsche Bank, which analysts and investors have long assumed Germany would treat as too big to fail if it encountered serious trouble.

Indeed, Deutsche Bank is central to Germany's economy, which is Europe's largest. It is one of the country's largest employers and lenders, and its CEO historically has been viewed as wielding power on par with the country's finance minister.

But concerns about whether the bank has enough capital to withstand the combination of a large Justice Department settlement, weak business conditions and Chief Executive John Cryan's plans to restructure the company have been gaining currency—and taking a toll on the bank's securities.

Ben DiPietro contributed to this article.

Write to Jenny Strasburg at jenny.strasburg@wsj.com and Andrea Thomas at andrea.thomas@wsj.com

(END) Dow Jones Newswires

September 27, 2016 13:25 ET (17:25 GMT)