Twitter shares plunged Tuesday after an earnings report that fell short of market expectations despite a jump in the number of active monthly users above 300 million.

Twitter reported that revenue during the first three months of this year was $436 million, while the San Francisco company had been expected to bring in about $456 million.

The one-to-many messaging platform reported a net loss in the quarter of $162.4 million as compared with a loss of $132.4 million on revenue of $250.5 million in the same period last year.

Twitter separately announced a deal to buy marketing technology company TellApart and a partnership with Google's DoubleClick platform to improve advertising performance.

Twitter shares dropped more than 17 percent to $42.63 in trading that followed release of the earnings figures.

The results came out ahead of schedule, through feeds on Twitter itself, about half an hour before the closing of the stock market.

"We are investigating the source of the leak," Twitter said.

Twitter chief executive Dick Costolo said revenue growth "fell slightly short of our expectations due to lower-than-expected contribution from some of our newer direct response products."

But he noted, "It is still early days for these products, and we have a strong pipeline that we believe will drive increased value for direct response advertisers in the future."

Costolo said that Twitter remained confident in its strategy for the long term success of the company.