At 5pm, the key index was down 15.97 points to 1,631.92.
Financial and commodities plays were pulled down by the prospect that the economic recovery could be derailed by the fast-spreading strain of coronavirus, sending key heavyweights lower.
Among banks, Maybank dropped eight sen to RM8.40, Public Bank shed 20 sen to RM20.46, CIMB lost 18 sen to RM4.12 and Hong Leong Bank fell 10 sen to RM18.48.
Meanwhile aluminium producer Press Metal slid 19 sen to RM7.18 while Petronas Chemicals skidded 13 sen to RM7.41.
The equities sell-off was precipitated by falling crude oil prices as hopes over the vaccine ending the pandemic were diminished by the growing number of infections in the US and Europe.
Brent crude dropped 1.4% to US$50.21 a barrel after hitting a high of US$52.48 a barrel last Friday. US crude was similarly beaten down 1.5% to US$47.27 a barrel.
On the Bursa Malaysia Energy Index, 22 of the 31 constituent counters dove into the red.
Bumi Armada lost two sen to 33 sen, Dayang shed three sne to RM1.12, Dialog lost three sen to RM3.38 and Hibiscus slid three sen to 57 sen.
Of actives on Bursa Malaysia, Technax fell two sen to 14.5 sen, Bintai Kinden rose seven sen to 73.5 sen and Iris added 0.5 sen to 39.5 sen.
Similarly in other parts of Asia, equities have been on the retreat.
Japan's Nikkei extended losses by 1% while South Korea's Kospi slid 1.6%. In China, the benchmark index lost 1.9% while Hong Kong's Hang Seng shed 0.7%.
In Australia, the ASX 200 was down 1%.
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