FRANKFURT — European leaders escalated their hard-line talk on Greece on Thursday, with the German finance minister threatening to leave the country to the mercy of financial markets if it does not meet the conditions set for receiving aid.

Aid will only be paid “if Greece actually does what it agreed to do,” said Wolfgang Schäuble, the German finance minister, during an interview Thursday with Deutschlandfunk radio.

If Greece does not meet the conditions it agreed to, as assessed by monitors from the International Monetary Fund, European Central Bank and European Commission, then payments will stop, Mr. Schäuble said.

“Then Greece has to see how it gets access to financial markets without help from the euro zone,” he said. “That’s Greece’s problem.”