Apple posted record revenue on Tuesday but faces new challenges in production of the iPhone as China shuts down major cities to contain the potentially deadly coronavirus, the company said.

Revenue in the first quarter of fiscal year 2020 totaled $91.82 billion, exceeding analysts' estimates of $88.37 billion and the $84.3 billion Apple posted in the same period a year ago.

Net income increased to $22.24 billion in the most recent quarter compared with $19.97 billion for the same period a year ago.

The company earned $4.99 a share, exceeding Wall Street's consensus estimate of $4.55.

"We are thrilled to report Apple's highest quarterly revenue ever, fueled by strong demand for our iPhone 11 and iPhone 11 Pro models, and all-time records for Services and Wearables," Apple CEO Tim Cook said in a statement. "During the holiday quarter, our active installed base of devices grew in each of our geographic segments and has now reached over 1.5 billion.

"We see this as a powerful testament to the satisfaction, engagement and loyalty of our customers — and a great driver of our growth across the board," he said.

Sales of the iPhone totaled $55.96 billion; analysts expected $51.5 billion.

Apple's stock is up about 27 percent since October, a gain many analysts attribute to the upcoming build-out of 5G wireless networks. In the last 52 weeks, the stock is up about 108 percent. The stock closed Tuesday at $317.69 a share, up $8.74, or 2.83 percent.

However, the spread of the coronavirus in China may challenge Apple's earnings in the coming quarter. China's government has barred employees in Shanghai and Suzhou from returning to work prior to Feb 9, a week longer than the traditional Lunar New Year holiday. Apple has at least two suppliers in Wuhan, capital of Hubei province, the center of the virus outbreak.

Most of Apple's iPhones are assembled in China by the Foxconn Technology Group in Zhengzhou and by Pegatron near Shanghai. Each is about 310 miles (500 kilometers) from Wuhan.

Apple's estimates for second-quarter revenue range from $63 billion to $67 billion. Analysts expect sales to total $62.41 billion. A year ago, revenue totaled $62.45 billion.

Cook attributed the gap between low and high estimates to potential problems created by the coronavirus.

"There's more uncertainty," he told CNBC. "It's a very fluid situation."

China's slow growth last year eroded Apple's sales of smartphones, but apps and smartwatches boosted revenue in the second half of the fiscal year ended in September. Investors will keep an eye on the impact of the coronavirus on sales and production in the coming quarter.

Last week, Bloomberg News reported that Apple had boosted iPhone production prior to the coronavirus outbreak to meet greater-than-expected demand. Production on high-end phones typically begins in September, so the coronavirus probably won't be a major factor in the months ahead.

But Apple plans to launch a low-cost version of the iPhone in February, and production of that model could be disrupted by the coronavirus outbreak.

Apple earned $12.7 billion in services revenue in the first quarter compared with the $13.07 billion analysts expected.

Other products, including the Apple Watch, AirPods and Beats Headphones, generated $10 billion in revenue compared with the consensus estimate of $9.52 billion.

With the smartphone market maturing, Apple introduced new services and accessories for its 900 million users worldwide.

Still, the iPhone generated about 61 percent of Apple's revenue in the first quarter of 2020. The company plans to release an update to its low-priced iPhone this year. The SE model sold for $399 when first released in 2016. Apple is betting volume sales will make up for the lower unit cost.