MUMBAI: The BSE benchmark Sensex today slumped by 347.50 points to touch a new three-week low on all-round selling in step with global markets which sank as the US braced itself for a government shutdown, political tension surfaced in Italy and tepid factory data jolted China.

Investors also took home some profits ahead of June quarter current account deficit data and as fears of more rate cuts by the RBI rose. However, Sensex rose by 760.05 points or 4.08 per cent in September, the first monthly gain since May.

After opening 83 points down at 19,643.89, the 30-share Sensex slipped for the major part of the session. It briefly tried to reverse the trend but relentless selling pressure forced it to touch day’s low of 19,320.73, before settling at 19,379.77 — down 347.50 points or 1.76 per cent.

The index had lost 166.58 points on Friday. The broad-based National Stock Exchange index Nifty dropped by 97.90 points, or 1.68 per cent, to 5,735.30. Also, SX40 index, the flagship index of MCX-SX, ended at 11,566.65, 174.19 points or 1.48 per cent down.

Brokers said global markets were spooked as a budget impasse in the United States threatens to shut down parts of the world’s largest economy for the first time 17 years.

The Eurozone was also affected by political tension as reports said Italian Prime Minister Enrico Letta called a parliamentary vote of confidence in his teetering left-right government on Wednesday.

Besides, disappointing Chinese PMI data for September that showed the factory sector grew marginally fuelled fears that the Asian giant was seeing patchy recovery. Indian metal stocks were hit by China factory data, said traders.

Sectorally, the BSE Capital Goods index was the worst hit as it lost 2.92 per cent, followed by BSE Banking sector index (2.84 per cent) as SBI, ICICI Bank, HDFC Bank and HDFC fell.