KANDAHAR, Afghanistan - Afghan security forces foiled two improvised explosive attacks after arresting at least three people and intercepting two vehicles -- one of them laden with explosives -- on Saturday in Kandahar.

Provincial police Chief Sayed Aka Sakib says the seizure of the cars resulted in information that led to the discovery of two booby traps that had already been set.

One of the bombs had been placed near a school in Kandahar, the second explosive was discovered in the border community of Spin Boldak.

Of those arrested, two are apparently Pakistani and one was an Afghan with ties to the troubled Panjwaii region west of the city.

Sakib says the cars did not appear to be rigged for suicide missions, but  were transporting a cache of explosives, likely to Taliban forces in the Panjwaii area.

"They were giving bombs from Pakistani Taliban to Afghan Taliban,'' Sakib said.

The interception of the explosives comes as NATO forces throughout southern Afghanistan brace for a spike in violence as the poppy harvest ends and recruits become available for insurgents.

The vehicles were stopped in District 7 of Kandahar City, a notorious area west of the provincial capital, where there have been gun battles between troops and insurgents.

One of the suspects appeared to be co-operating with police, conceding to Afghan reporters at a hastily called news conference that he had been paid C$150 to drive one of the vehicles from the border area with Pakistan to Kandahar City.

Sakib says the two vehicles drove in tandem from the border.

One of them was a taxi cab, a favourite vehicle of the Taliban when transporting explosives or fighters.

Afghan police seized artillery shells and mines that witnesses said appeared to be improvised devices that had already been assembled in Pakistan.

NATO forces have aggressively been hunting down bomb-making factories in southern Afghanistan, uncovering a number of them in recent months.

Afghan police appeared to have been tipped off to the movements of the vehicles as Sakib said they followed them once they entered the city.

Once the suspects were in custody, authorities were warned about the improvised explosives that had already been planted.

Canadian army explosive experts were called to deal with the bomb outside the Kandahar city school, while the second explosive in Spin Boldak was defused by local police, said Sakib.

The military was not available Saturday night to confirm the statement.

The hunt is continuing for more suspects, Sakib added.

Spring is the time when the Taliban have traditionally launched a wave of bombings and ambushes.

They have threatened to launch an "offensive'' every year, but have been largely limited to hit-and-run roadside bombing or suicide attacks.

NATO has since late 2006 carried out a campaign of killing top and mid-level Taliban commanders.