Already bruised by worries over North Korea and upcoming French elections, global investor sentiment was further hurt by weak US economic data. Though a host of Chinese economic data beat market expectations, they failed to trigger market reactions as investors had already been optimistic following a recent string of positive numbers out of the country. Similarly, Singapore's strong export numbers for March did little to lift dour investor mood following the central bank's cautionary tone last week.
"Local news such as the Singapore non-oil domestic exports and MAS monetary policy, though positive, may have already been partly factored into stock prices given the year-to-date performance of the Singapore stock market," said Liu Jinshu, director of research, NRA Capital.
Singapore shares fell 0.9% and were the worst performers in the region. The Singapore market was closed on Friday for a holiday.
"The lower open today created a snowball effect that perpetuated more selling as traders cut their losses from leveraged positions, according to some brokers," he said.
Losses were broad-based with industrials, financials and telcos being the worst-performing sectors.
Telecommunications firm StarHub Ltd and real estate operator City Developments Ltd fell about 2% each and were the biggest losers on the index. Philippine shares, which gained 0.6 percent last week in their third straight weekly gain on the back of strong net foreign inflows, fell 0.5%.
Analysts say they believe the spate of gains resulted in profit booking. Megaworld Corp, which was one of the biggest gainers last week, was the worst performer on the index. Telco PLDT Inc, a heavyweight in the telecommunications sector and on the index, was 2% lower.
The Stock Exchange of Thailand index fell 0.6%, dragged down by energy and consumer stocks, while Malaysia and Vietnam eked out small gains.