Mumbai, Feb 11 (IANS): Continuing with their downslide for the fourth day in a row, key Indian equity indices again opened weak on Thursday, with weakness in other Asian markets adding more fuel to the battered sentiments.

The 30-share sensitive index (Sensex) of the Bombay Stock Exchange (BSE) opened just a tad lower at 23,758.46 against the previous day's close at 23758.90 points, but around an hour into trading the index lost significant ground, with a loss of 172.51 points, or 0.73 percent at 23,586.39 points.

At the National Stock Exchange, the broader Nifty was down 56.10 points, or 0.78 percent, at 7,159.60 points.

In the past three trading sessions, Monday-Wednesday, the Sensex has shed 858.07 points or 3.61 percent, while the Nifty has lost 273.4 points or 3.78 percent. Both the indices also touched a new 52-week low of 23,636.72 points and 7,177.75 points, respectively, on Wednesday.

"The US markets ended Monday's session on a negative note after giving away their early gains. The volatility continued as the price of crude oil showed wild swings during the day," said Angel Broking in an analysis on Thursday morning.

"Oil prices initially increased on reports that there was an unexpected decline in inventories. But oil prices pulled back, as the report also showed increase in gasoline and distillate fuel inventories as well as record high inventories at a key delivery points," it said.

"The European markets ended Wednesday's session in the green as strong rebound in bank stocks propelled the market higher."