ATHENS — Greece missed a crucial debt payment to the International Monetary Fund, the fund said early Wednesday, deepening a crisis that has haunted world leaders and financial markets over the past week.

The development came as Greece’s European creditors each rejected an 11th-hour attempt by Athens to extend the country’s international bailout program.

Greece is not technically in default, but missing the payment of 1.5 billion euros, or about $1.7 billion, is yet another warning that the country will probably be unable to meet its other obligations in coming weeks, to its bond holders and to the European Central Bank. That might make the bank, one of the country’s chief creditors, less willing to continue emergency loans that have been propping up Greek banks for the past several months.