Six people have been killed and several others still missing after a boat carrying over 50 people capsized in a remote area of northwest Pakistan, according to officials who said on Thursday that there were slim chances of finding survivors.

The boat was carrying passengers along the Indus river from Shangla to Haripur district in the Khyber Pakhtunkhwa province on Wednesday when it overturned.

Rescuers were dispatched as soon as the incident was reported but the difficult mountainous terrain delayed the response.Teams of the Pakistan Army’s Special Service Group had been dispatched to the site as well, he added.