U.S. weapons maker Lockheed Martin Corp reported better-than-expected quarterly profit on Tuesday, helped by a strong performance at its ships and helicopters unit and venture capital gains, and reiterated its sales guidance for 2022.

But the company also said it had been informed by the U.S. Federal Trade Commission that its planed purchase of Aerojet Rocketdyne would raise antitrust concerns, leaving Lockheed either to abandon the transaction or fight a federal lawsuit in order to close the deal.

The $4.4 billion deal announced in late 2020 is Lockheed's first large acquisition under new Chief Executive Jim Taiclet. It would reshape the competitive landscape for solid rocket fuel missiles which are used with jets and drones.

Lockheed reported net operating earnings were $2 billion in the fourth quarter, or $7.47 per share, surpassing analyst estimates of $1.98 billion, or $7.12 per share, according to Refinitiv data. Full-year earnings per share were $22.76, beating analyst estimates of $22.44.

Net sales were $17.7 billion during the fourth quarter, just beating analyst estimates of $17.67 billion.

Last October, the Bethesda, Maryland-based company lowered its 2022 full-year revenue outlook to $66 billion - sending its shares tumbling - citing challenges with its supply chain. Lockheed reaffirmed that 2022 revenue guidance on Tuesday.

U.S. President Joe Biden has not signaled he plans to slash the 2023 budget for Lockheed's biggest customer, the Pentagon, despite progressive Democrats calling for a reduction in military spending and the U.S. withdrawal from Afghanistan.

The company said it now expects full-year 2022 earnings per share to be about $26.70, ahead of analysts' expectation of $26.36 per share, according to data from Refinitiv.

Lockheed's biggest unit, which makes F-35 fighter jets for the United States and its allies, delivered 142 of the stealthy planes in 2021, three more than originally planned.

During 2021 the company sent $7 billion back to shareholders in the form of dividends and share repurchases, and paid an effective tax rate of 16.9%.