Pakistani authorities on Friday said they had arrested four Islamic State militants plotting attacks in the city of Lahore, just weeks after the military declared it had halted the Middle East-based movement's expansion into the country.

The four were plotting attacks on government targets when they were seized in a raid along with 1.6 kg of explosives as well as fuses and detonators, the city's Counter Terrorism Department said in a statement.

"The terrorists had planned to kill officials on a large scale" and were about to launch their attack when agents acting on a tip raided their hideout near Lahore's Moon Market, the department said.