ExxonMobil reported lower first-quarter profits Friday, citing a fall in refining margins and a decline in natural gas prices that offset robust output in Guyana.

ExxonMobil, which had targeted the second quarter to complete a takeover of US shale player Pioneer Natural Resources, reported profits of $8.2 billion, down 28 percent from the year-ago period.

Revenues dipped four percent to $83.1 billion.

While commodity prices for liquid hydrocarbons rose slightly and the company continued to score impressive volumes from Guyana, those benefits were more than offset by a 32 percent drop in natural gas prices.

The company's energy products business also experienced a big drop in earnings on weaker refining profit margins despite reporting record first-quarter refining throughout.

ExxonMobil steered $6.8 billion towards shareholders in dividends and stock repurchases during the quarter. 

Chief Executive Darren Woods cited growth in Guyana and efficient refining operations as key strengths.

"Looking ahead, we're making great progress on our plans to grow the earnings power of our existing businesses from investments in advantaged assets and higher-value products, and further reduce structural costs," Woods said.

Shares dipped 0.9 percent in pre-market trading.