By Carla Mozee, MarketWatch

European stocks stumbled Friday, with losses coming ahead of a crucial weekend deadline for Greece and its creditors to work out their differences and steer the debt-laden country away from default.

The Stoxx Europe 600 fell 0.6% to 393.97 and no sectors were moving higher.

High-level talks between Greek and European officials this week have failed to break a long-standing stalemate over an economic reform plan for Greece, and now Greece's creditors have said they want a deal in place (http://www.theguardian.com/business/2015/jun/25/weekend-deadline-greece-after-negotiations-draw-blank) before markets open on Monday.

The International Monetary Fund said Thursday if Greece doesn't make a $1.7 billion debt repayment due June 30, the Hellenic nation will immediately be in arrears (http://www.marketwatch.com/story/imf-greece-would-immediately-be-in-arrears-if-it-misses-june-30-payment-2015-06-25) on its debt to the institution.

Greece's Athex Composite fell 1.5% to 769.98.

Germany's DAX 30 was down 0.4% to 11,427.11, and France's CAC 40 lost 0.6% at 5,012.98, with only two components edging higher.

U.K.'s FTSE 100 dropped 0.7% to 6,750.60. Spain's IBEX 35 lost 0.5% to 11,251, and Italy's FTSE MIB gave up 0.6% to 23,499.61.

Greek government bond prices edged higher, leaving the yield on 2-year debt down 3 basis points at 21.28%, according to Tradeweb. The yield on 10-year bonds fell 9 basis points to 10.68%.

In corporate news, shares of K&S AG (SDF.XE) rallied 33% on takeover talks with Potash Corp. (POT) (POT)

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