An 18-hour fight between the militants and the Afghan security forces in Kabul ended early Monday after 36 insurgents were killed in the attacks along with eight policemen and three civilians.

A militant arrested in the attacks on the Afghan capital and three other cities has confessed that the assault was carried out by the Haqqani network, a group of fighters with ties to the Taliban and al-Qaida, Associated Press quoted a top Afghan security official as saying on Monday.

Thirty-six insurgents were killed in the attack with eight policemen and three civilians. The attack was carried out to prove that the insurgency was not weak as claimed by Nato and they can still penetrate Afghan security after 10 years of war, said Interior Minister Besmillah Mohammadi.

Earlier, militants launched attacks on US, German and British embassies, Afghan government buildings and Nato bases on Sunday at 1.30 pm that continued through the night, with explosions and gunfire on the streets.

Reports also suggested that apart from Kabul, the eastern capitals of Paktia, Logar and Nangarhar provinces also came under attack on Sunday as suicide bombers tried to storm a NATO base, an airport and police installations there. The fighting at the Afghan parliament building on the southwest side of the city ended just before 8 a.m.

The violence shows that the Taliban and their allies are far from beaten. Taliban spokesman Zabiullah Mujahid told the AP on Monday that the attacks did not mark the start of the insurgents' spring offensive, which he said would begin shortly.

"It is a message for the spring offensive but it has not yet started," Mujahid said. "The offensive will start shortly and it will be announced with its name and the purpose of the operation," he added.

The attacks have raised concerns about security and is also seen as a setback for US President Barack Obama, who wanted to show the campaign against the Taliban as a success before the Nato troops depart by the end of 2014.

Afghan President Hamid Karzai was yet to make a statement after he was locked down at his presidential place by the guards as the attacks broke out.