JOHANNESBURG - The South African rand fell almost 2% on Friday as the U.S. dollar extended gains after receiving a boost from a very hawkish Federal Reserve policy announcement and rising Treasury yields.

The rand traded at 17.9300 against the dollar at 1556 GMT, 1.77% weaker than its previous close.

The dollar index, which measures the greenback's value against six major currencies, was up more than 1.3% at 112.730.

In the absence of major local drivers, the rand tends to take its cue from global factors including dollar moves.

South African state-owned utility Eskom said on Friday it would reduce the level of scheduled power cuts over the weekend and that more outages were probable next week.

Stocks on the Johannesburg Stock Exchange (JSE) fell, mostly due to declines in the mining index.

The benchmark all-share index closed 2.85% lower at 63,416 points, while the Top-40 index fell 2.96% to 57,109 points.

The South African government's benchmark 2030 bond was weaker in afternoon trade, with the yield rising 18 basis points to 10.770%.

(Reporting by Alexander Winning and Anait Miridzhanian; Editing by Stephen Coates)