Chinese internet giant Alibaba said on Friday it would buy Hong Kong's South China Morning Post, following weeks of speculation over the future of the English- language newspaper.

"(Alibaba) has entered into a definite agreement to acquire the South China Morning Post (SCMP) and other media assets of SCMP Group Limited," the Chinese firm said in a statement.

The once globally renowned paper was founded in 1903 and has long given international readers an insider's perspective on Hong Kong and the mainland, but profits and sales have in recent years been hit by an industry-wide decline.

Readers' trust has also dipped as a more pro-Beijing editorial policy has not gone unnoticed in a city that saw tens of thousands take to the streets last year to protest against mainland interference.

Analysts have said a link to Alibaba would boost the SCMP's online presence but could further erode its editorial independence.

In a letter to the newspaper's readers following the announcement of the sale, however, Alibaba executive vice chairman Joe Tsai vowed the SCMP would be "objective, accurate and fair" and have "the courage to go against conventional wisdom".