KARACHI (Reuters) - The Karachi stock market closed flat on Friday as early gains on hopes of healthy corporate results were eroded towards the end amid concerns regarding the law and order situation in Karachi. At least 10 people were killed and 20 injured in the country's biggest city on Friday as rival groups fought pitched battles in the city's eastern neighbourhoods, police and officials said. "There was some interest in the morning as investors are expecting healthy results from leading companies, particularly in the fertiliser and banking sectors," said Ashraf Zakaria, a dealer at brokers Ali Hussain Rajabli and Co. "But the violence in the city resulted in negative sentiment and investors, fearing that it could escalate further over the weekend, offloaded holdings before the close," he said. The Karachi Stock Exchange's benchmark 100-share index ended 0.02 percent, or 2.01 points, higher at 12,476.77. During the day, the index touched a high of 12,543.18. Volume rose sharply to 126.25 million shares from 70.32 million on Thursday, but dealers said that did not show a broad interest in the market as 60 million shares were traded in the rights issue of NIB Bank alone. In the currency market, the rupee strengthened to close at 86.14/19 to the dollar, little changed from the previous day's close of 86.20/25 as dollar supplies remained healthy. The rupee hit a record low of 86.50 in May, but has been steady since, largely due to increased remittances from Pakistanis working abroad. According to official data, remittances rose to a record $11.2 billion in 2010/11 fiscal year, an increase of 25.77 percent from the previous year. In the money market, overnight rates closed at the top level of 13.90 percent, unchanged from the previous day and despite a central bank injection of 90 billion Pakistani rupees ($1.04 billion) in the interbank market. "The market is very tight and that is why despite such a heavy injection, the rates did not fall," said a bank dealer. APP adds from Islamabad: Islamabad Stock Exchange (ISE-10) witnessed bullish trend on Friday as index ended 11.76 higher to close at 2800.66. Senior Equity Dealer of Ismail Iqbal Securities Karachi Zaheer Ahmed said that amendment in the Capital Gains Tax (CGT) by Federal Board of Revenue (FBR) created positive sentiments in the markets. He said the participation of majority investors in the markets increased volume. He added that fertilizer and oil sectors remained favourite for the intra-day investors. Manager of First National Equity Islamabad M.M Hassan told APP that the oil price raise in the international market led bullish rally in the oil sector. Total shares traded were 39,884, which were up by 15,824, as compared to 24,060 share traded the previous day. Out of 133 companies, whose shares were traded on Friday, the price of shares of 79 companies increased while that of 54 decreased. The price of top gainer Siemens Engineering increased by Rs.30.08 while Bhanero Textile decreased by Rs.7.80. Fatima Fertilizer, Fauji Fertilizer Bin Qasim and Engro Corporation were top volume leaders with 25,000, 5,000 and 4,584 shares respectively.