The markets continued to trade on a weak note in the noon deals. The Sensex was at 16,569, down 128 points, and the S&P CNX Nifty shed 40 points to 4,975. Earlier in the day, the Sensex fell to 16,495.

Salil Sharma, technical analyst, partner,  said: "We expect the Nifty to trade above the support of 4,900 while the upper band is at 5,200. If the Nifty breaks out above 5,200 then it could head towards 5350."

Meanwhile, the European markets opened in the red. FTSE opened at 5,132, down 1%, CAC40 index was at 2,996, lower by 31 points and the DAX was at 5,544, lower by 95 points.

Back home, ONGC was the top loser among the Sensex stocks, down 2.5% to Rs 262. Tata Power was down 2.3% to Rs 99. Hero MotoCOrp, Maruti Suzuki, Tata Steel, Hindustan Unilever, SBI, DLF, Hindalco, ICICI Bank and ITC were also trading lower by 1-2% each.

On the other hand, Bharti Airtel, Larsen & Toubro, Reliance Industries and Mahindra & Mahindra were among the notable gainers on the benchmark index.

The shares of Reliance Anil Dhirubhai Ambani Group were reeling from intense selling pressure. The stocks shed over 5% each on back of news reports that Anil Ambani, the group promoter being probed by the Central Bureau of Investigation (CBI) in 2G scam. The CBI said the role of Anil Ambani was being probed as three jailed corporate honchos of his company RADAG had distanced themselves from any wrongdoing in the 2G spectrum scam," reports said.

Most of the sectoral indices barring consumer durables index were trading in the negative territory. BSE PSU index was the top loser on the charts. The index shed 1.3% or 100 points to 7,425. Power, Realty, Metal, Bankex, FMCG, Oil & Gas, Auto and IT indices were also amongst the losers, down 0.6%-1% each. Capital Goods and healthcare indices were also trading marginally lower.

GAIL India was the top loser among the PSU stocks, down 3.2% to Rs 413. Indian Bank shed 2.7% to Rs 212. SAIL, Container Corporation, PNB, Power Finance Corporation and Bank of India were also among the prominent losers on the index. Among the power stocks, Reliance Infrastructure, Reliance Power, Siemens, Tata Power, Adani Power, NTPC and Torrent Power were among the top losers.

The broader markets were trading on a subdued note. The BSE mid-cap index was at 6,173, up 8 points and the small-cap index was down 4 points to 6,937.

The overall breadth was negative as 1,287 stocks were declining while 1,190 stocks were advancing.