Stock indices closed mixed on the uncertainty over Greece's debt crisis. Greek Prime Minister Alexis Tsipras said in a speech on Wednesday that Greeks should vote "no" in Sunday's referendum. He added that "no" would not mean that Greece have to leave the Eurozone.

The head of the Eurogroup Jeroen Dijsselbloem said on Thursday that if Greeks vote "No" on Sunday, it could mean that Greece have to leave the Eurozone. He added that Greeks should not expect better conditions if they vote "No".

Greek Finance Minister Yannis Varoufakis signalled on Thursday that he will resign if Greeks vote "Yes" in the referendum on Sunday.

Earlier, he said that a deal with Greece's creditors on Monday.

Meanwhile, the producer price inflation in the Eurozone improved slightly in May. Eurozone's producer price index was flat in May, missing expectations for a 0.1% increase, after a 0.1% decline in April.

On a yearly basis, Eurozone's producer price index dropped 2.0% in May, in line with expectations, after a 2.2% fall in April.

Eurozone's producer prices excluding energy fell 0.3% year-on-year in May. Energy prices dropped 6.4%.

The European Central Bank's (ECB) its minutes of March meeting on Thursday. According to the minutes, the ECB said in its minutes that there is no need to increase its bond-buying programme. The central bank added that it could adjust its bond-buying programme if needed.

The ECB wants to "look through recent volatility in financial markets and maintain a steady monetary policy course.

The ECB Chief Economist Peter Praet said that Eurozone's economy continued to improve.

Markit's and the Chartered Institute of Purchasing & Supply's construction purchasing managers' index (PMI) for the U.K. increased to 58.1 in June from 55.9 in May, exceeding expectations for a rise to 56.5.

A reading above 50 indicates expansion in the construction sector.

The increase was driven by a rise in the house-building sector, but both commercial and civil engineering activity also increased.

The Nationwide Building Society released its house prices data for the U.K. on Thursday. UK house prices declined 0.2% in June, missing expectations for a 0.5 percent rise, after a 0.2% rise in May. May's figure was revised down from a 0.3% increase.

On a yearly basis, house prices fell to 3.3% in June from 4.6 percent in May, missing forecast of a 4.3% gain.

Indexes on the close:

Name Price Change Change %

FTSE 100 6,630.47 +21.88 +0.33 %

DAX 11,099.35 -81.15 -0.73 %

CAC 40 4,835.56 -47.63 -0.98 %