FRANKFURT — The European Central Bank sought Monday to discourage speculation that it might act far more aggressively to contain borrowing costs for countries like Spain, while issuing a rare rebuke to government officials who have encouraged such speculation.

“It is absolutely misleading to report on decisions which have not yet been taken,” the central bank said in a statement. The report referenced, by the German magazine Der Spiegel, led to a temporary sell-off of United States Treasury securities while briefly lifting European stocks Monday

The magazine reported Sunday that the central bank was considering setting upper limits on borrowing costs for some euro zone countries. To enforce such limits, the bank would have to promise to buy bonds in whatever quantity was necessary, a risky commitment.

The central bank rarely comments on the rampant, often thinly sourced speculation about its internal deliberations that is common in the European media. That the bank did so could reflect its frustration about such news coverage. Der Spiegel did not cite any sources in its article.