KANDAHAR, Afghanistan — Police in Kandahar say they thwarted a plot Sunday to blow up a provincial building in the city, on the same day U.S. envoy Richard Holbrooke visited the region to get a first-hand look at the war.

The triumph came just days after a deadly suicide attack in Kabul that took 28 lives, including those of eight militants.

Holbrooke was at Kandahar Airfield, under a tight security blackout, to talk to military commanders.

"We had a good talk about the overall security situation in the south, counter narcotics and the possible increase of troops," said Dutch Maj.-Gen. Mart De Kruif, the current NATO commander in the southern region, in a statement following the meeting.

Later in Kabul, Holbrooke met with Afghan President Hamid Karzai and signed a declaration that contains measures aimed at reducing civilian deaths in the war against the Taliban.

His visit to Kandahar took place within hours of three Taliban suspects being arrested in a lightning raid Kandahar's District 2, a mostly residential section of the city.

A cache of weapons and explosives was also seized by local police in a separate, nearby raid.

Afghan National Police Gen. Matiullah Qati credited the training and support his forces received from Canadian police mentors for the success of the operation.

The plot apparently involved gunman seizing the provincial Office of Skills Development in the heart of the war-ravaged city and strapping explosives at key points around the building.

The militants planned to kill the night watchman, make enough noise and commotion to attract the police, Qati told a news conference for the local media Sunday.

The Taliban planned to withdraw from the building and detonate the explosives once police had been drawn inside, bringing down the structure, he claimed.

"Thank God it didn't work," Qati said in an interview.

"Their cunning tactics would have brought huge casualties to police forces, but they failed."

The Taliban have taken credit in the last year for a series of bloody attacks in Kandahar, including the spectacular truck bomb and rocket assault on the city's prison, which set free over nearly 900 inmates, as well as the suicide bombing at police headquaters that killed six officers.

Qati said the details of the latest foiled attack were obtained through confessions of the three suspects.

It's unclear whether the Kandahar plot was meant as a followup to last week's attack on the Justice Ministry and the Office of Corrections in Kabul.

"The enemy have lost the strength to engage with police forces directly (so) now they are carrying out suicide attacks, planting IEDs, wag (ing) hit-and-run war and assassination attempts in the province," he said.

"Now the enemy (is) relying on planting mines widely in large numbers in the city and out of the city. Luckily we have now the capability to detects their mines and defuse them by the help of PRT (provincial reconstruction team) and Canadian forces."

RCMP Insp. Joe McAllister, commander of the Canadian Civilian Police Contingent, didn't have many details about the alleged plot, but accepted the praise and said the Afghan police have made progress in counter-terrorism operations.

He said in addition to the plot, Qati was the subject of an assassination attempt while on the way to work Sunday morning.

A militant with a bomb in a wheelbarrow blew himself up, injuring two police officers, one of whom later died.

McAllister said the Afghans are getting better at tracking terror cells.

The time was not so long ago when a suicide bomber blew himself up, Kandahar police would simply close the book.

"Their belief was that the bad guy was dead, but we've got them changing their mind on that and through the intelligence process we're trying to figure out who is building these bombs and deploying them into the city."