ISTANBUL — President Recep Tayyip Erdogan of Turkey raised the stakes in a long-running diplomatic spat with Germany on Friday, dismissing the threat of an informal German economic embargo and rejecting calls to release several German citizens held in Turkish jails.

In recent days, German officials have offered unusually strong criticism of Turkey’s government. The German foreign, finance and justice ministers advised Germans against traveling to or conducting business in Turkey.

Though the ministers stopped short of imposing a travel ban or economic embargo, their comments were problematic for the sputtering Turkish economy. Germany is Turkey’s main trading partner, and more than 3.3 million German tourists visited Turkey last year, more than came from any other country.

On Friday, Mr. Erdogan scoffed at the ministers’ warnings.

“I want to remind my German friends, and to all the world, you do not have the power to defame Turkey,” Mr. Erdogan said at a fund-raising event for a hospital. “You do not have the power to scare us with these kinds of things.”