Stocks extended their decline on Monday morning as crude oil resumed a move lower. 

The S&P 500 was down 0.57%, the Dow Jones Industrial Average fell 0.72%, and the Nasdaq declined 0.46%.

Crude oil fell after Saudi Arabia detailed plans to diversify from an oil-reliant economy. Oil revenue currently accounts for 80% of the country's income, but has taken a hit as commodities tumble. King Salman said the country's 'Vision 2030' blueprint aims to create more jobs and encourage foreign investment. Deputy Crown Prince Mohammed bin Salman hopes to raise non-oil revenue by $100 billion by the end of the decade. 

West Texas Intermediate crude oil was down 1% to $43.27 a barrel after briefly turning positive earlier in the session.

The number of new homes sold in March in the U.S. fell 1.5% to a seasonally adjusted rate of 511,000, according to the Commerce Department. However, the underlying trend towards an improving housing market remained strong: the measure remained above 500,000 for its fourth straight month in a row, its best winning streak since the beginning of 2008. February's pace was also revised up to 519,000.

The Federal Reserve will meet on Tuesday with an announcement set for Wednesday afternoon and while the chances of an interest rate hike are slim, investors will be keen to gauge how willing members are to move at the next meeting in June.

"While we assign a low probability of a rate hike, sentiment may be impacted by Fed comments about the strength of economic health and implied likelihood of a June rate hike," said Terry Sandven, chief equity strategist at U.S. Bank Wealth Management.

Fed funds futures only price in a rate hike with odds greater than 50% in November, nearly a year after December 2015's initial liftoff, according to CME Group. The chance of an April rate hike is currently priced in at 2%, while a June hike has a 17% probability. September has a 47% chance.

It's also a massive week for earnings with Apple (AAPL - Get Report) , AT&T (T - Get Report) , Twitter (TWTR - Get Report) , Facebook (FB - Get Report) and Amazon (AMZN - Get Report) set to report their quarterly performances.

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Gannett (GCI - Get Report) was up 2.5% after offering to buy Tribune Publishing (TPUB) in a deal worth $815 million, including $390 million in debt. The publishing company proposed $12.25 a share in cash, equivalent to a 63% premium on Friday's close. Tribune shares surged 60%.

Xerox (XRX - Get Report)  fell more than 13% as restructuring costs related to its planned split reduced earnings from a year earlier. The printing company earned 3 cents a share in its first quarter, down from 19 cents a share in the year-ago quarter. On an adjusted basis, earnings of 22 cents a share missed expectations by a penny. Revenue fell 4% to $4.28 billion.

KKR & Co. (KKR - Get Report) was slightly lower after swinging to a first-quarter loss tied to extreme market volatility at the beginning of the year. The private-equity firm reported a loss of 73 cents a share, far from profit of 57 cents a share in the year-ago period. The company's portfolio depreciated 0.9% over the first quarter.

Ball (BLL - Get Report) was on watch after clearing a major obstacle to the closing of its ¿5.4 billion ($7.8 billion) purchase of the U.K.'s Rexam (REXMY) . The can maker struck a $3.42 billion agreement to sell assets to Ardagh to meet regulatory conditions of the larger deal.

Valeant Pharmaceuticals (VRX) added more than 3% after naming Joseph Papa as its new chairman and CEO. Papa resigned as CEO of Perrigo (PRGO - Get Report) on Sunday. Papa will replace current CEO Michael Pearson effective early May. 

Halliburton (HAL - Get Report) has rescheduled its earnings report until next month after initially being scheduled to release Monday morning. The oil-services company is currently clearing regulatory hurdles tied to its planned merger with Baker Hughes (BHI) . 

Caterpillar (CAT - Get Report) was upgraded to neutral with a $78 price target from sell at Goldman Sachs. Analysts said the company is leveraged to higher construction demand in China.