Dialog Telekom lost 25 cents to close at 13.50 rupees while John Keells Holdings closed 50 cents lower at 114.50.
The All Share Price Index dropped 0.
68 percent (16.88 points) to end at 2,499.61 while the more liquid Milanka fell 0.
81 percent (24.61 points) to 3,005.24. Turnover was 144.7 million rupees.
A bus bombing by Tamil Tiger separatists killed 20 people before the market opened, while another bomb went off in a bus about an hour and a half after the market closed.
The market has declined by 1.52 percent or 38.79 points during the week, compared to the Friday before.
The biggest deals were done on Environment Resource Investment Company with its share picking up 2.
50 rupees to close at 37.00 Friday.
The Colombo Fort Land and Building Company share closed up 1.50 rupees at 28.25, adding 21.98 million rupees to total turnover.
The weak sentiment in the market is likely to continue as company earnings have not been up to the expectations of investors, analysts said.
Kelani Tyres shares were also up four rupees at 59.
50.
But index heavy counters traded lower.