Turkey's stock exchange dropped 0.22 percent, or 208.51 points, to open at 93,297.72 points Friday.
On the last transaction day of the week, the banking and holding sector indices fell 0.43 percent and 0.17 percent, respectively.
Among all sector indices, the construction sector index posted the best performance, up 0.46 percent, while the electricity sector was the worst, down 2.14 percent.
On Thursday, Borsa Istanbul's BIST 100 closed at 93,506.22, down 2.08 percent or 1,987.08 points, with a trading volume of 7.6 billion liras ($1.4 billion).
The USD/TRY exchange rate increased to 5.4620 as of 9.30 a.m. local time (0630GMT) on Friday. It was 5.4160 at Thursday's close.
The euro/lira exchange rate fell to 6.1960 by market open -- from 6.2060 at the previous close -- and one British pound traded for 7.1330 Turkish liras over 7.1130 at the previous close.
The price of Brent oil dropped to $70.75 per barrel as of 10.00 a.m. local time (0700GMT) Friday. It was $71.88 on Thursday.