NEW YORK (Reuters) - Comcast Corp (>> Comcast Corporation) reported slightly lower-than-expected quarterly revenue on Thursday and said it lost video subscribers, while analysts raised questions about growth prospects for the No. 1 U.S. cable operator's internet business.

Comcast's video business has been pressured as more consumers cancel their cable packages in favour of cheaper streaming options from companies like Netflix Inc (>> Netflix). Video accounts for roughly 44 percent of revenue in the cable business, Comcast's largest segment.

AT&T Inc (>> AT&T) and Verizon Communications Inc (>> Verizon Communications) have also reported video subscriber losses.

Shares of Comcast were down 0.2 percent at $36.75 at mid-afternoon after tumbling nearly 4 percent in premarket trading as investors shrugged off higher-than-expected earnings.

The company said it lost 125,000 video subscribers in the third quarter. It said in September that it might lose up to 150,000 due to recent hurricanes and increased competition in the pay-TV industry.

Consumers now have more choices for streaming television over the internet at cheaper prices than cable. Such alternatives include Dish Network Corp's (>> Dish Network) Sling service, Sony Corp's (>> Sony Corp) PlayStation Vue and AT&T's DirecTV Now.

Comcast has said it is well-positioned for changes in viewing habits because of its high-speed internet, or broadband, business, which added 214,000 subscribers in the quarter.

But on a conference call, Wall Street analysts said that business' growth had slowed. The company had added 330,000 broadband subscribers in the year-earlier period.

The analysts asked how Comcast viewed the competitive landscape as rival AT&T expands its fiber-based internet service into areas Comcast serves.

Chief Executive Brian Roberts said the company had anticipated AT&T's expansion.

"Our view is to deliver the best product, period, and we will constantly increase speeds," he said. "That's why we've been so focussed on Wi-Fi."

In May, Comcast introduced its cloud-based XFi service, which allows users to set up their home Wi-Fi, shut off children’s devices at bedtime and troubleshoot problems from an application on their mobile phones, website or television.

Roberts also said Comcast's Xfinity Mobile service, which competes with wireless carriers like AT&T and Verizon, had surpassed 250,000 customer lines since its introduction in May.

Net income attributable to Comcast rose 18.5 percent to $2.65 billion(£2.01 billion pounds), or 55 cents a share.

Excluding special items, earnings per share came to 52 cents. Analysts on average had expected 50 cents, according to Thomson Reuters I/B/E/S.

Revenue fell 1.6 percent to $20.98 billion from the year-earlier period, when the company's NBC broadcast network benefited from the 2016 Olympics. Wall Street had forecast $21.04 billion.

(Reporting by Anjali Athavaley; Editing by Diane Craft and Lisa Von Ahn)