Russia's largest state companies saw their share prices plummet, with retail banking giant Sberbank losing 24%, leading oil company Rosneft shedding 14%, and natural gas monopoly Gazprom down 16.5%.
Trade on the dollar-denominated RTS was halted at 6:00 p.m. local time (14:00 GMT) after sliding 13.68% to 549.43. The exchange said it would remain closed "until the end of the next trading day [Monday] on the orders of the Federal Service for Financial Markets."
The RTS, along with the ruble-denominated MICEX, have seen 10 straight weeks of decline, bringing their indices down to levels last seen in December 2004.
Friday's freefall began quicker on the more liquid MICEX, which closed after less than four hours of trade, having fallen 14.24% to 513.62.
The RTS is down 77% from its May high-point, while MICEX has lost nearly 74%.
Russian securities were dealt a severe blow on Thursday, when the rating agency Standard & Poor's cut Russia's credit rating outlook from "stable" to negative". S&P warned of further defaults among banks and corporations, despite the government's $200 billion bailout scheme.
The falling oil price is also fueling panic on the Russian markets, with the implied drop in revenue from crude sales. The crude price in New York fell almost 5% to $63 on Friday despite an output reduction announed by OPEC.
The weakening of the ruble against the dollar, and speculation of a devaluation of the national currency, has also eroded confidence on the stock markets. The ruble lost 23 kopeks on Friday to hit 27.3 against the dollar, a two-year low.
The Central Bank has been forced to sell dollars to support the ruble, depleting its international reserves, which have contracted from their $598 billion August highpoint to $515.7 billion.
