Dhaka, July 18 - Protesters here began a 'long march' against a dam across the border in northeastern India as Bangladesh's main opposition rejected Indian Prime Minister Manmohan Singh's assurance that no work would be started without holding talks.

Activists of Nirvik, an environmental organisation, Friday set out on a six-day 264 km march to Sylhet to mobilise public opinion against the dam project.

The protesters started their long trek on foot from Muktangan after a rally where leaders of Nirvik and other organisations urged the government to take necessary steps to prevent the Indian government from constructing the dam.

Singh told Prime Minister Sheikh Hasina earlier this week that it would do 'nothing anti-Bangladesh' on the project over the Barak river, but the Bangladesh Nationalist Party (BNP) said it was 'dissatisfied'.

Mounting pressures on the government and on India, the BNP Friday renewed its demand for recall of Indian High Commissioner Pinak Ranjan Chakravarty over a remark at a seminar that it termed as 'interference in Bangladesh's affairs'.

'We cannot rest assured at the statement of the Indian prime minister made during his meeting with Prime Minister Sheikh Hasina,' party vice chairman M.