The blue-chip Dow Jones industrial average, which fell 151.26 points Wednesday, was down 27.50 points to 9,205.40.
The tech-heavy Nasdaq composite index, which dropped 75.73 points in the previous session, was ahead 14.05 points to 1,660.39.
The broader New York Stock Exchange composite index was down 2.66 to 555.26 while the Standard & Poor's 500 index was down 2.69 to 1,074.40.
The American Stock Exchange composite index was down 4.74 points to 818.27 while the Wilshire Smallcap Index was down 1.37 to 641.19.
Big Board volume declined to an estimated 489.50 million shares from 575.10 million shares changing hands during the same period Wednesday.
Analysts said stocks were mixed as continued fears of bio-terrorism countered positive sentiment that might have stemmed from the most recent batch of corporate results.
Fears surrounding anthrax contamination were exacerbated after a CBS News employee working in the offices of anchor Dan Rather tested positive for exposure to the skin version of anthrax.
On the earnings front, Merrill Lynch reported earnings per share of 44 cents, 3 cents ahead of estimates but considerably below last year's 94 cents level.
Texas Instruments reported a loss per share of 3 cents after the closing bell, 1 cent smaller than expectations.
Eli Lilly and Merck reported third quarter earnings that were in line with Wall Street expectations.
Eli Lilly, which recently lost the exclusive rights to produce anti-depressant Prozac, reported third-quarter bottom line results of 66 cents. The company said that its earnings per share in the fourth quarter is likely to be 59 to 61 cents, with 2002 results at $2.70 to $2.80.
Merck, with third-quarter net income of 84 cents, also reiterated its expectations of full-year earnings per share of $3.12 to $3.18.
General Motors posted a stronger-than-expected third quarter net of 85 cents, 5 cents higher than expectations, but the results were offset by a profit warning for the fourth quarter. The company now expects fourth quarter net income of 50 cents, 21 cents below the First Call consensus estimate.
Boeing Co., with earnings of 88 cents, said its full year revenue could be below the original $58 billion target, with operating margin also below the original forecast of 8.25 percent.
Coca-Cola said its third quarter net income, excluding the negative effect of currency, came at 45 cents. Further, the company reconfirmed its full-year earnings and unit case volume growth guidance.
Meanwhile, on the economic front, the Labor Department said new claims for state unemployment benefits during the week ended Oct. 13 rose by 6,000 to a seasonally adjusted annual rate 490,000. Economists on Wall Street were expecting first time claims to rise by 12,000 during the week.
But, the Labor Department also said the four-week moving average of claims, considered a more reliable indicator because it eliminates week-to-week fluctuations, rose to 491,250 -- its highest level in more than 10 years. And, the total number of people receiving jobless benefits rose by 152,000 to 3.65 million -- its highest level in more than 18 years.
Meanwhile, U.S. Treasury prices inched higher. The 30-year bond added 3/32 to 101. Its yield, which moves in the opposite direction of its price, slipped to 5.31 percent from 5.32 percent late Wednesday.
In Europe, stock prices ended lower in moderate trading in London, Frankfurt and Paris, pressured by weakness in technology stocks. The London International Stock Exchange's blue-chip FTSE-100 index lost 85.4 points, or 1.64 percent, to 5,118.0. The German DAX index fell 51.94 points, or 1.12 percent, to 4,592.88 and the French CAC-40 index lost 73.42 points, or 1.66 percent, to 4,338.09.
Analysts said stocks fell after software giant SAP lowered its full-year revenue target. SAP, the world's biggest business software publisher, said 2001 revenue will grow by 15 percent. The company had previously forecast full-year sales growth of more than 20 percent. It also reported disappointing third-quarter earnings.
Earlier in Asia, prices on the Tokyo Stock Exchange ended lower in moderate trading as investors locked in profits, particularly in the recently rising technology sector, following a weak performance Wednesday on Wall Street. Japan's blue-chip Nikkei Average of 225 selective issues, which rose 117.63 points Wednesday, fell 280.60 points, or 2.60 percent, to 10,474.85.
Analysts said stocks moved lower on selling led by technology issues after Wall Street dropped Wednesday amid a disappointing assessment of the U.S. economy and news that anthrax was found on Capitol Hill.
The Nikkei index fell below the 10,500 level in thin trading, but selling at the lower end of range was limited due to an improving market outlook, traders said.
Elsewhere in Asia, prices also ended lower in moderate trading on the Hong Kong Stock Exchange. The blue-chip Hang Seng Index sank 380.20 points, or 3.70 percent, to 9,880.61 -- its lowest close since September 27.
Analysts said broad-based issues suffered from selling on fears that biological attacks in the United States will further dampen consumer confidence.
Meanwhile, prices ended slightly lower on the South Korean Stock Exchange, pressured by weakness in technology and telecom issues. The Kospi Composite Index slipped 4.08 points, or 0.77 percent, to 524.21.
Prices also ended slightly lower on the Taiwan Stock Exchange as export oriented technology shares came under pressure on ongoing pessimism over a recovery in the sector. The Weighted Index slipped 5.93 points, or 0.16 percent, to 3,811.20.
Elsewhere around the region, prices ended lower in moderate trading on the Australian Stock Exchange. The blue-chip All Ordinaries Index fell 35.90 points, or 1.13 percent, to 3,134.10, pressured by profit-taking in the natural resources sector.