The new leader of the Afghan Taliban has called for unity among his fighters, promising to continue insurgency in his first message.

The audio message purportedly from Mullah Akhtar Mohammad Mansoor also included comments about peace talks, though it was not immediately clear whether he supported them or not.

Taliban spokesman Zabiullah Mujahid sent the audio to journalists and others on Saturday.

The Taliban on Thursday confirmed that former leader Mullah Omar had died and said they elected Mansoor as his successor.

The Afghan government announced on Wednesday that the reclusive mullah had been dead since April 2013.

Mullah Omar was the one-eyed, secretive head of the Taliban whose group hosted Osama Bin Laden's al Qaida in the years leading up to the September 11 2001 attacks.

"We should keep our unity, we must be united, our enemy will be happy in our separation," Mansoor purportedly said in the message. "This is a big responsibility on us. This is not the work of one, two or three people. This is all our responsibility to carry on jihad until we establish the Islamic state."

The new leader of the Taliban is seen as close to Pakistan, which is believed to have sheltered and supported the insurgents through the war. Whether he will be keen to sit down for peace talks with the Afghan government remains in question. The Taliban pulled out of talks scheduled for Friday in Pakistan after Mullah Omar's death became public.

Taliban attacks against Afghan officials and forces have intensified with their annual warm-weather offensive. Local security forces increasingly find themselves under attack as Nato and US troops ended their combat mission in the country at the end of last year.