ISTANBUL — First, Prime Minister Recep Tayyip Erdogan criticized the bold move by Turkey’s central bank this week to raise interest rates sharply to halt the decline in the country’s currency, telling reporters that higher borrowing costs would lead to inflation — an argument that contravenes accepted economic logic.

Mr. Erdogan’s economic adviser, Yigit Bulut, then did little to reassure skittish investors, suggesting that the prime minister would do something that would be “very positive for the markets,” but did not say exactly what Mr. Erdogan’s plans were.

The remarks only added to jitters in financial markets, which have battered the Turkish stock market and in recent weeks sent the currency, the lira, to historic lows. While Turkey has suffered along with other developing nations from the “tapering” of bond purchases by the United States Federal Reserve and the threat of rising global interest rates, its problems go beyond that to basic questions about the stability of the government and its ability to grapple with the economy’s problems.

To some extent, Turkey and Mr. Erdogan are victims of their own success, having created an attractive investment climate that brought in billions in dollar-denominated lending, particularly after the financial crisis of 2008. Officials in Western capitals, including President Obama, came to see him as the prime example of a leader who could meld democratic values, Islam and economic prosperity.