NEW YORK (TheStreet) -- The Dow Jones Industrial Average extended losses in the afternoon session amid a series of poor earnings results. The S&P 500 was also pressured by earnings, while the Nasdaq was boosted by deals news in the pharmaceutical sector. 

The S&P 500 was down 0.07%, the Dow fell 0.42%, and the Nasdaq added 0.5%.

Travelers Companies (TRV) was the worst performer on the Dow, dropping more than 3% after missing both earnings and revenue estimates in its first quarter. 

DuPont (DD) fell 2.5%, as quarterly sales dropped 9.5% to $9.17 billion. Revenue was lower due to declining volumes and the negative impact of a stronger dollar.

Verizon (VZ), another Dow component, slipped 0.24% despite posting quarterly profit of $1.02 a share, 7 cents higher than analysts' estimates. Revenue of $31.98 billion was nearly 4% higher year over year, though it came in below forecasts.

IBM (IBM) was also pressuring the Dow, as revenue fell nearly 12% to $19.59 billion during the first quarter. Foreign exchange headwinds contributed an 8% impact.

United Technologies (UTX), a component of the Dow, was an exception, gaining 0.51% after reporting a 20% rise in quarterly profit, though revenue missed forecasts. The aerospace company affirmed previous sales and earnings guidance for the full year in spite of a stronger dollar.

Harley-Davidson (HOG) was the worst performer on the S&P 500 after revenue dropped 3.8% to $1.51 billion. The motorcycle maker reported a 1.3% decline in volume of new units over the quarter due to "aggressive discounting." Harley-Davidson also reduced its motorcycle-shipments forecast for the year.

Under Armour (UA) reported a double-digit decline in profit. Costs rose over the quarter as the athletic clothing company acquired two fitness-tracking companies. Shares fell more than 5%. 

Baker Hughes (BHI) tumbled 2.2% after reporting a loss of $589 million compared to profit of $328 million a year earlier. The oil services company also increased layoffs to 17% of its total workforce over the first quarter.

Packaging Corp. of America  (PKG) reported earnings of $1.01 a share, 7 cents higher than expected. Sales of $1.43 billion missed estimates of $1.44 billion. Shares slid nearly 10%. 

The Nasdaq was boosted by pharmaceutical stocks after Teva Pharmaceuticals (TEVA) made an offer to buy competitor Mylan (MYL) for $82 a share in a cash-and-stock bid. Teva expects to close the deal by year's end, creating $2 billion in annual synergies. However, Mylan made clear on Friday that it was not interested in a sale.

Teva climbed 1.5%, while Mylan surged 8.1%. Nasdaq components Gilead Sciences (GILD) and Vertex Pharmaceuticals (VRTX) participated in a sector rally.

Crude oil prices fell below $56 a barrel ahead the expiration of May futures Tuesday afternoon and U.S. inventory data from the Energy Information Administration Wednesday morning. West Texas Intermediate crude closed down 2.3% to $55.10 a barrel.

Gold and silver prices rebounded on Tuesday as worries over Greece's future and escalating tensions in the Middle East triggered demand for the safe-haven asset. Gold futures for June delivery added 0.3% to $1,197.70 an ounce, while silver for May delivery climbed 0.3% to $15.93 an ounce.

Greece's future looked more uncertain as doubts arise as to whether the nation can come to an agreement this week with European creditors for further debt relief. Greece's finance minister and European counterparts have placed a self-imposed deadline of Friday for debt talks, though many remain unconvinced a deal will be made in time.

On Monday, the Greek government issued a decree for state-owned companies and public pension funds to transfer cash into the central bank's coffers. Economists estimate that Greece will run out of money by early May unless it can secure a debt agreement.

U.S. warships are reportedly on course for the Yemeni coast, according to The Wall Street Journal. A fleet will be stationed off the coast to keep watch on Iranian flotilla potentially harboring weapons for militia in Yemen.

"Geopolitics continue to simmer away as tension persists in the Middle East with unrest in Yemen, while the debate is ongoing as to 'will we-won't we' see Iranian oil sanctions lifted at some point in the future," said Matt Smith, commodity analyst at Schneider Electric.