NEW YORK (TheStreet) -- Greek markets stumbled on Friday after the International Monetary Fund walked away from bailout talks with Greece.

The IMF sent its negotiators home to Washington, D.C., from Brussels, citing a lack of progress in the discussions. The main issues that are said to remain unsolved include cuts to Greek pensions, changes in the labor market and Greece's government budget.

The news weighed on other European markets, as well. Greece's creditors, which include the IMF as well as its eurozone counterparts, have been insisting that the country commit to new economic reforms before it can receive the last 7.2 billion euros left in Greece's 240 billion-euro bailout.

Greece has been struggling to pay its debts, salaries and pensions without that final installment. That installment in the country's bailout fund has been pending since last year.

The country has a roughly 1.6 billion-euro IMF debt repayment due on June 30, which it will likely be unable to pay without reaching a deal and receiving more funds. If Greece defaults on that repayment, it could result in the country being pushed out of the eurozone.

Greece also owes still larger repayments to the European Central Bank in July and August.

The news that the IMF abandoned talks came as optimism had been increasing that a deal would be reached by the deadline. Discussions are expected to continue among eurozone officials ahead of a meeting of finance ministers next week in Luxembourg.

"At the end of the talks there was absolute unanimity that Greece will work intensively and full steam ahead... in the coming days to solve all remaining issues," German Chancellor Angela Merkel said, according to Reuters.

The next meeting of eurozone finance ministers is schedule to take place next Thursday.

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