Stocks were lower again by mid-morning Tuesday as the energy sector continued to sell off despite an uptick in crude prices. 

The S&P 500 was down 0.32%, the Dow Jones Industrial Average dipped 0.54%, and the Nasdaq slid 0.17%.

The energy sector was the worst performer on markets after the International Energy Agency warned prices likely will remain lower as Iranian production exacerbates an oversupply crisis. Major oilers Exxon Mobil (XOM - Get Report) , Chevron (CVX - Get Report) , Royal Dutch Shell (RDS.A - Get Report) , Total (TOT - Get Report)  and BP (BP - Get Report) were lower, while the Energy Select Sector SPDR ETF (XLE - Get Report) slid 1.6%.

Crude oil moved higher despite IEA's warning. The energy watchdog said conditions have worsened since Iranian oil began to flood the market after sanctions were lifted, while the Organization of Petroleum Exporting Countries has failed to come to an agreement on reduced production. West Texas Intermediate crude oil climbed 0.4% to $29.81 a barrel on Tuesday morning. 

"It is very hard to see how oil prices can rise significantly in the short term," the IEA said in its monthly industry report. "Persistent speculation about a deal between OPEC and leading non-OPEC producers to cut output appears to be just that: speculation."

Fresh data on the labor market helped to support the Federal Reserve's decision to hike rates for the first time in nearly a decade last year. Job openings climbed to 5.6 million, its second highest level ever, in December, the same month the central bank moved on rates. Voluntary quits increased 7%, indicating that workers were confident in other opportunities in the jobs marketplace. 

Japan's Nikkei bore the brunt of selling in the region as China's markets remained closed for the Lunar New Year. The Nikkei tumbled more than 5% as investors poured into safe-haven assets as global growth fears persisted and oil prices continued to slide. The interest rate on Japan's benchmark 10-year bond became negative for the first time ever. The yield on the bond fell by 0.05 percentage points to minus 0.03%.

The financials sector was under selling pressure for the second day in a row. European banks UBS (UBS - Get Report) , Deutsche Bank (DB - Get Report) and Credit Suisse (CS - Get Report) were lower, while U.S. institutions Bank of America (BAC - Get Report) and Goldman Sachs (GS - Get Report) slid.

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Uncertainty over the Federal Reserve's rate hike plans also contributed to downward momentum. Fed Chair Janet Yellen will address Congress on Wednesday and investors will be closely watching for signs on Fed sentiment. Wall Street remains concerned the central bank will move forward with additional rate hikes following December's move even as the economy shows signs of weakness.

"The markets will have their ear to the ground to listen for any clues as to whether Yellen still sees March as the correct timing for the next rate hike," said Chuck Butler, managing director of EverBank Global Markets. "She'll have all of the markets' attention, as the data cupboard is light this week and we have to wait until Friday to see January's retail sales."

Coca-Cola (KO - Get Report) reported a better-than-expected quarter as aggressive cost cuts improved margins. The beverage company earned 38 cents a share, a penny above estimates. Adjusted revenue, excluding currency headwinds and divestures, declined 1%.

21st Century Fox (FOXA) fell more than 4% after a weaker quarter as its film business dragged on overall revenue. The media giant reported an 8.4% decline in sales in its December quarter, mostly dragged on by its sale of Sky Italia and Sky Deutschland a year earlier, though weaker home entertainment sales also pressured the topline.

Wendy's (WEN - Get Report) posted fourth-quarter adjusted earnings of 12 cents a share, topping Wall Street estimates by a penny. The hamburger chain posted revenue of $464.4 million, which came in under forecasts. 

Chesapeake Energy (CHK - Get Report) continued its slide on Tuesday even as the oil company assured investors it has no plans for bankruptcy. Shares tanked a day earlier on reports the company had hired restructuring attorneys as it struggles to cope with a tough commodities environment.

Viacom (VIA.B) shares were on watch after a mixed quarter. The media company missed sales estimates on weaker ad revenue and a poor comparative box office. Sales in its filmed entertainment unit slid 15%.

Regeneron Pharmaceuticals (REGN - Get Report) fell more than 5% on disappointing sales of its key eye-disease drug. Sales of Eylea increased 44% in its fourth quarter, slowing from 65% growth a quarter earlier. Adjusted earnings of $2.83 a share missed estimates of $3.36.