KABUL: Afghan troops backed by Western air power killed at least 60 militants near the Pakistan border, Afghanistan's intelligence agency said on Wednesday, in one of the biggest single assaults against the Taliban-linked Haqqani network.

US officials say Washington has intensified its drive against the network in an attempt to deal a lasting blow to the militants in Afghanistan before foreign combat forces depart this year.

About 300 Haqqani insurgents and foreign fighters came under intensive fire on Monday when they tried to storm Afghan bases in Ziruk district of Paktika province, the National Directorate of Security (NDS) said in a statement.

The Nato-led international force declined to comment.

The Haqqani network, which professes obedience to Taliban leader Mullah Mohammad Omar, is believed to have been involved in some of the most deadly attacks of the Afghan war.

The group has been blamed for attacks on hotels popular with foreigners in Kabul, the bombing of the Indian embassy in the capital, a 2011 attack on the US embassy and several big attempted truck bombings.

The United States blacklisted the group as a terrorist organisation in 2012. It also accuses Pakistan's powerful spy agency of supporting the network and using it as a proxy in Afghanistan to gain leverage against growing influence of its India. Pakistan denies that.

Monday's battle occurred in the southeast province of Paktika which shares a long and porous border with lawless areas in Pakistan where foreign fighters and the Haqqani network are believed to be based.

Insurgents pledged to disrupt this month's presidential election with a campaign of violence, but the vote passed off relatively peacefully.

As the country readies for an expected second round run-off in June, there is concern the conditions will be more favourable for militant attacks.