Mumbai, April 14 -- Benchmark stock indices Sensex and Nifty closed nearly 1% lower on Monday as the failure of US-Iran negotiations heightened concerns of a prolonged conflict driving crude oil prices sharply higher. The 30-share BSE Sensex tumbled 702.68 points or 0.91% to settle at 76,847.57. During the day, it dived 1,681.93 points or 2.16% to 75,868.32. The 50-share NSE Nifty plunged 207.95 points or 0.86% to end at 23,842.65. From the 30-Sensex firms, Maruti, InterGlobe Aviation, Bajaj Finance, Reliance Industries, Tata Consultancy Services and HDFC Bank were the biggest laggards. ICICI Bank, NTPC and Axis Bank were the winners. The US and Iran failed to reach a peace deal at their historic 21-hour talks in Pakistan, leaving the fate of a tenuous two-week ceasefire in doubt, with both sides attempting to hold each other responsible for the collapse of the negotiations. Brent crude, the global oil benchmark, jumped 7.73% to $102.6 per barrel. In Asian markets, South Korea's benchmark Kospi, Japan's Nikkei 225 index and Hong Kong's Hang Seng index ended lower, while Shanghai's SSE Composite index settled marginally higher. European markets were trading lower. "Markets continue to derive limited support from last week's ceasefire framework, which remains intact for now and is encouraging selective buying interest along with a buy-on-dips approach. This comes despite an initial negative reaction to the breakdown of US-Iran peace talks and the announcement of a US naval blockade in the Strait of Hormuz, which pushed crude prices above $100/bbl," Vinod Nair, Head of Research, Geojit Investments Limited, said. Elevated oil prices are raising concerns around inflation, currency stability, and broader macro balances, thereby weighing on overall sentiment, Nair added. US markets ended on a mixed note on Friday. "The weakness was primarily driven by escalating geopolitical tensions following the collapse of US-Iran talks, which triggered a sharp spike in crude oil prices and weighed on global sentiment," Ajit Mishra, SVP, Research, Religare Broking Ltd, said. The BSE MidCap Select index dropped 0.82% and SmallCap Select index declined 0.33%. Auto edged lower by 2.10%, followed by Energy (1.34%), Services (1.31%), Oil & Gas (1.25%), Consumer Discretionary (1.21%), IT (1.17%), and BSE Focused IT (1.02%). Telecommunication, Utilities and Power were the winners. A total of 2,573 stocks declined, while 1,790 advanced and 201 remained unchanged on the BSE. Foreign Institutional Investors (FIIs) turned buyers on Friday, buying stocks worth Rs.672.09 crore, according to exchange data. On Friday, the Sensex jumped 918.60 points or 1.20% to settle at 77,550.25. The Nifty climbed 275.50 points or 1.16% to end at 24,050.60. Stock markets will remain closed on Tuesday for Baba Saheb Ambedkar Jayanti....