In a major breakthrough in the war o­n terrorism the police today announced the discovery of a long-sought cache of bomb-making material destined for use against Western targets in Singapore.

Four tonnes of the explosive fertiliser ammonium nitrate, often used in truck bombs, was found buried in a palm oil estate after the arrest of a suspected member of the al-Qaeda-linked Jemaah Islamiah (JI) terror group, a police spokesman told AFP .

Rumours of the existence of the huge stockpile of the key bomb-making ingredient have circulated since security forces in neighbouring Singapore foiled a plot to bomb western targets there more than a year ago.