Dhaka - Police in Bangladesh arrested four suspected Islamist militants from the country's northern Gaibandha district Thursday, a day after the authorities beefed up security amid threats by militants against prominent political leaders.

Officials said the members of the elite anti-crime Rapid Action Battalion captured the activists of Jama'atul Mujahidin Bangladesh, an outlawed organization responsible for a number of past militant attacks, from a village of the district.

Security forces in a pre-dawn raid also seized huge quantities of bomb making ingredients, electronic equipment, batteries, grenade casings, chemicals and booklets on religious subjects from the possession of militant suspects, a district police officer said.

In the southern city of Khulna, the battalion also recovered a makeshift bomb from the entrance of a mosque belonging to the city's Muslim Ahmadiya sect.

Bangladeshi authorities have strengthened security arrangements across the country ahead of Monday's parliamentary elections, following intelligence reports citing threats from militants against the country's two former prime ministers -Sheikh Hasina Wajed and Khaleda Zia - who are leading two rival political alliances in the polls.

In recent days law enforcement officers have arrested around 15 suspected Islamist militants, and have seized explosives.

Bangladesh's December 29 election is first in seven years, returning the country to democracy, and ending two years of the army- backed unelected civil administration of Fakhruddin Ahmed. (dpa)