Feb 2 (Reuters) - Yahoo Inc said on Tuesday it was exploring strategic alternatives in addition to the continued pursuit of the reverse spin-off of its Internet business.

The company also said it would cut about 15 percent of its workforce and close offices in five locations.

Shares of Yahoo, which also reported fourth-quarter results, fell 1.4 percent in after-hours trading on Tuesday.

The company said it would simplify its product portfolio and that it had begun to explore divesting non-strategic assets.

Yahoo on Tuesday also reported a 15 percent fall in adjusted quarterly revenue as it struggles to keep its share of online search and display advertising in the face of tough competition from Facebook Inc and Alphabet Inc's Google.

Chief Executive Marissa Mayer, who joined Yahoo in 2012 from Google, has been trying to revive the Internet pioneer's core media and online advertising business by spending heavily to draw more users to its websites.

Mayer proposed in December that Yahoo spin off its main business, which includes its search engine, digital advertising units and its email service, after Yahoo abandoned efforts to sell its stake in Chinese e-commerce giant Alibaba Group Holding Ltd. But the company had provided few details.

Traffic acquisition costs (TAC), the amount Yahoo spends to attract users to its websites, rose to $271 million in the fourth quarter ended Dec. 31, from $74 million a year earlier.

Yahoo's revenue - after deducting fees paid to partner websites - fell to $1.00 billion from $1.18 billion.

The company reported a loss of $4.43 billion, or $4.70 per share, in the quarter, compared with a net income of $166.3 million, or 17 cents per share, a year earlier.

Excluding items, Yahoo earned 13 cents per share, in line with analysts' average expectations.

Up to Tuesday's close of $29.06, Yahoo's shares had fallen 35 percent in the past 12 months.

(Reporting by Abhirup Roy and Anya George Tharakan in Bengaluru and Deborah M. Todd in San Francisco; Editing by Savio D'Souza)