Security is being tightened in Kabul ahead of the arrival of Richard Holbrooke a day after the Taliban attacked the Afghan capital, killing 20 people.

Government troops were deployed heavily through the city on Thursday, hours before the US special representative to Afghanistan and Pakistan was due to arrive to discuss US policy in the region.

"We will have to take tougher security measures," Mohammad Hanif Atmar, Afghanistan's interior minister, said a day after Taliban fighters and suicide bombers attacked three government buildings.

Hamid Karzai, Afghanistan's president, has ordered security forces to "act quickly" against those who raided the country's justice and education ministries and the prisons directorate.

He said in a statement that "security forces have the ability to protect the lives and property of the people of Afghanistan".

Resurgent Taliban

Holbrooke's visit to Kabul, which is part of a broader tour of the region, comes as Barack Obama, the US president, focuses on combating Taliban and al-Qaeda linked fighters based in Pakistan and Afghanistan.

"The information we are getting is that the events on Wednesday have no bearing on Holbrooke's travel plans," Hamish MacDonald, Al Jazeera's correspondent in Kabul, said.

"But clearly, if those events are not affecting his plans, they will certainly affect the meeting he will hold. He will surely be asking leaders here why they cannot even secure government infrastructure in the capital."

Washington has already said that it will send thousands of extra troops to Afghanistan to help Kabul fight the Taliban, which has been resurgent in the last few months.

The most deadly attack in Kabul on Wednesday took place at the justice ministry, where armed men killed at least 10 ministry employees, Atmar said.

Five attackers were shot dead and three died after they detonated bombs.

A Taliban spokesman told Al Jazeera that the attacks were aimed at avenging the mistreatment of some of its men held in Afghan jails.

Pakistan link

The Afghan government has in the past blamed attacks in the country on Taliban and al-Qaeda-linked fighters based in Pakistan's tribal areas over the Afghan-Pakistani border.

Most of the fighters there are thought to be those who fled Afghanistan during the US-led invasion of the country in 2001.

The attacks on the Afghan capital underscore the depth of the security challenges facing nearly 70,000 US and international troops stationed across the country.

Obama is expected to approve the deployment of about 30,000 extra troops to Afghanistan in the next few days.