ISTANBUL — When police arrested a man near the office of Turkish Prime Minister Recep Tayyip Erdogan in central Ankara last month, officers first thought they had caught a suicide bomber. It quickly turned out that the man, Tugrul Bayir, did not have a bomb with him, but his action was potentially explosive nonetheless. Bayir told police he wanted to stage a spectacular protest because of his credit card debt, which amounted to about $17,000. Like Bayir, millions of Turks are in the red, and many are sinking ever-deeper into debt.

The total debt on Turkey’s 57 million credit cards stands at around $45 billion, and the volume of nonperforming consumer loans is at $14 billion, a 20% increase since the end of last year. According to the Dunya daily, around 1.7 million credit card holders were unable to pay their debt in the first nine months this year, compared with 277,000 in the whole of 2009.

Authorities are reacting by tightening rules for credit card use and consumer loans. But critics say more than 2 million Turks have already defaulted.

In a sign of the government’s concern about the problem, Erdogan used a speech in Fethiye in southwestern Turkey last weekend to warn Turks of high interest rates on credit card debt. “My citizens should be careful when they get a credit card,” Erdogan said, adding that credit card holders should not spend more than they earn. The prime minister said debtors risk losing everything they own if they default. “They will take away everything you own,” he said.