Insurgents on Sunday attacked an Afghan army post in eastern Paktika province, leaving five soldiers and at least 18 fighters dead, the US-led multinational force said.
Six soldiers were hurt, three seriously, before the attackers were fended off by mortar fire from nearby military bases, said a multinational force statement.
Foreign soldiers were embedded with the Afghan soldiers but suffered no casualties, it said.
Officials from the multinational force told Aljazeera that one of its soldiers was killed in Helmand in southern Afghanistan.
Police in the province on Saturday killed six Taliban fighters and wounded four in the mountains of Garmser district, said Ghulam Rasool, the district police chief.
The clash continued on Sunday, during which three officers were wounded, Rasool said.
Also on Sunday, in a flood-hit province, authorities found bombs planted under the car of a senior Afghan Red Crescent official and outside a government refugee office.
And in Kabul, the education minister teamed up with the top US general in Afghanistan to thwart attacks on schools that have killed 41 students and teachers over the last year.
This year has seen an alarming upsurge in insurgent violence, sparking the heaviest fighting since the ouster of the Taliban regime in late 2001.
In the country's south and east, Nato- and US-led forces are pursuing a fierce campaign against insurgents to extend the reach of Afghanistan's central government.
Insurgents attacked an army
post in Paktika on Sunday
The insurgents - a shadowy combination of Taliban-led fighters, opium traffickers and paid tribesmen - have gone after teachers, students, health workers and aid officials as well as security forces.
Mohammed Hareef Atmaf, the education minister, said on Sunday insurgents burnt 144 schools to the ground over the past year to discredit the government's ability to build a future for Afghanistan.
The top US general in Afghanistan, Lieutenant-General Karl Eikenberry, signed a deal with Atmaf on Sunday to provide $300,000 for a programme to rally communities to protect their schools.
The minister claimed insurgents were switching their attacks to unguarded targets because of the country's strengthening domestic military and police forces. However, those forces are still far from adequate to stabilise the country.
Police officer dead
On Saturday night, a clash among police in the Andarab district of northern Baghlan province left one police officer dead and four wounded.
Kamin, a provincial police official who goes by only one name, said it was not immediately clear what caused Saturday's gunfight.
Taliban fighters are launching
attacks on almost a daily basis
In southeastern Ghazni province, authorities averted two bomb attacks on relief officials. The province was hit by floods on August 4, but some areas have yet to receive aid, partly because of insecurity caused by the presence of Taliban fighter.
An intelligence official, acting on a tip, found a bomb planted under the parked car of Afghan Red Crescent provincial chief Sayed Gulam Ahmed Mujahid, who said he had no idea who would have tried to assassinate him.
The bomb was safely defused.
Officials also found a bomb in a sack outside the Ghazni provincial refugee office. An intelligence official who came to investigate grabbed the bag and blew himself up, said provincial spokesman Abdul Ali Fakory.
Meanwhile, police in the eastern Kunar province said they were investigating who fired two mortar rounds at a house on Saturday, wounding 20 civilians, including women and children.
Two other mortars landed next to a nearby Indian road construction company, which was apparently the target of the attack, said General Abdul Jalal Jalal, the provincial chief of police.
In other violence, a suspected Taliban insurgent was killed and another wounded after fighters attacked and clashed with police in Aka Ghar district of the southern Zabul province late on Saturday, said district police chief Momuand Khan. There were no police injured.
Separately, insurgents blocked the main Kandahar-Kabul highway in Zabul province on Sunday, hijacking three trucks and torching two, said Noor Mohammad Paktin, the provincial chief of police.