Jakarta. Incumbent governor Basuki "Ahok" Tjahaja Purnama is ahead of competitor Anies Baswedan in the bitterly fought Jakarta election, an opinion survey published on Saturday (15/04) showed.

The survey by Jakarta-based Charta Politika was released just four days before the runoff election, and after months of campaign that have been overshadowed by religious and ethnic tensions.

The survey was also among several published after the first-round election on Feb. 15, in which Ahok won against former education minister Anies but did not secure more than 50 percent of the vote, forcing an election runoff on April 19.

Saturday's survey showed that 47.3 percent of nearly 800 respondents favored Ahok and deputy governor Djarot Saiful Hidayat while 44.8 percent supported Anies and running mate Sandiaga Uno, a businessman.

As many as 7.9 percent of respondents remained undecided according to face-to-face interviews conducted between April 7 and 12. Charta Politika claimed the survey had a 3.5-percent margin of error.

The Saturday poll contradicted another survey released by Saiful Mujani Research and Consulting (SMRC) on Wednesday, which showed 47.9 percent of respondents favoring Anies, 1 percent ahead of Ahok.

Mounting religious and ethnic sentiments have surrounded Ahok's bid for re-election, after he made a public comment in September last year against the use of the Koran for political campaigning.

The Christian of Chinese descent is currently on trial on blasphemy charges, and Muslims have demanded that he step down as governor in a series of mass rallies that have shaken Jakarta in the last five months.

But Ahok remained popular as a tough reformer, gaining 42.9 percent of the vote in the Feb. 15 election while Anies gathered 39.9 percent.

The April 19 second-round election will come just a day before prosecutors are set to demand a prison sentence for Ahok.