In April, gunmen in a rented hotel room fired on Afghan President Hamid Karzai at a military parade in Kabul as he sat in the the review stands. Karzai escaped injury, but the attack killed three people, including a lawmaker.
Taliban violence has spiked across Afghanistan in recent days, including an ambush on a NATO convoy on Sunday, attacks on police checkpoints and a roadside bomb targeting a police convoy. More than 90 people were killed over four days - most of them reportedly Taliban insurgents.
Kabul so far has been spared the violence afflicting much of Afghanistan, but there are signs the Taliban and other militant groups have gained a foothold in neighboring provinces. And the capital suffered spectacular bomb attacks this year against an international hotel and the Indian Embassy.
Interior Ministry spokesman Zemarai Bashary said more than 5,000 extra police were drafted for what he described as the biggest operation of its kind in Kabul since 2001, when U.S.-led forces ousted the Taliban government.
The Interior Ministry said the capital's police would search buildings and cars to "prevent any disruptive actions by the enemy."
A lawmaker from Kandahar who is critical of Karzai's government said the police deployment has more to do with protecting the government's reputation than reassuring the public.
"Unless they bring some comprehensive changes in the security, this deployment will not affect people's confidence," Khalid Pashtun said.
Pashtun said there has been a steady increase in kidnappings, robberies and other crimes this year.
"People are afraid to leave their house after 7 p.m.," he said.
One policeman deployed near a wide avenue where gunmen shot at Karzai in April was 22-year-old police recruit Farid Ahmad.
"I am still a student, but this was an order from the commander of the academy that we should come out and search the vehicles," he said.
In an ambush last week, insurgents wielding assault rifles gunned down three female aid workers about an hour's drive south of Kabul.
To the west, insurgents have been regularly attacking U.S.-led coalition and NATO supply convoys, burning fuel trucks and killing NATO and coalition soldiers.
To the east, the Tag Ab valley of Kapisa province has become the scene of near-daily clashes and airstrikes by the U.S.-led military coalition in Afghanistan.
Afghan and NATO officials insist that the nearly seven-year effort to bring stability to Afghanistan is progressing.
However, the security operation in Kabul is the second time this year that authorities have taken extraordinary measures to reassure Afghans that cities are safe from a Taliban assault.
In June, Afghan and NATO commanders mustered thousands of troops to clear militants from a strategic valley within striking distance of Kandahar, Afghanistan's main southern city.
Overall, insurgent attacks jumped by 50 percent in the first half of 2008 from the previous year, according to recent data from the Afghanistan NGO Safety Office, a Kabul-based group that advises relief groups on security.
More than 3,200 people - mostly militants - have been killed in insurgency-related violence this year, according to an Associated Press count based on figures from Western and Afghan officials.
Most of the violence is concentrated in the south and east, where Taliban sympathies run strongest and militant bases in neighboring Pakistan are closer.
In the latest violence: - Zabul Deputy Gov. Gulab Shah Alikheil said 32 Taliban fighters died during a four-hour battle Sunday. Alikheil said the militants ambushed a NATO supply convoy escorted by private security, sparking the battle that drew in Afghan soldiers. The Interior Ministry said nine Afghan private security guards died.
- In Kandahar province, a roadside blast killed 10 police officers on patrol Saturday, said Matiullah Khan, the provincial police chief. Khan blamed the Taliban. Militants have increased their attacks against Afghan police, who are often poorly equipped and poorly trained. More than 1,000 police died in insurgent attacks last year.
- Taliban insurgents attacked police checkpoints in Nad Ali district of southern Helmand province Friday, sparking clashes that killed 23 militants, the Interior Ministry said Sunday.
- Afghan and foreign troops clashed with militants Saturday in a mountainous area of Zabul province, killing seven militants, said district chief Fazel Bari.
- In eastern Paktika province, police clashed with militants Saturday in Shwak district, killing four insurgents, said Ruhulla Samon, spokesman for the provincial governor. Afghan and foreign troops clashed with insurgents in the same area Thursday, killing seven militants, the Defense Ministry said.