KABUL: A remote-controlled roadside bomb killed three police officers in eastern Afghanistan on Sunday, an attack the Taliban claimed as the opening round of their spring offensive.

The bomb exploded in Ghazni province beneath a police convoy that was traveling to the district of Zana Khan to take part in a military operation against insurgents, Mohammad Ali Ahmadi, the province’s deputy governor, told The Associated Press.

He said the blast destroyed the vehicle carrying Col Mohammad Hussain, the deputy provincial police chief, killing him and two other officers.

Ahmadi said two officers also were wounded in the insurgent operation, adding that it clearly targeted Hussain.

Taliban spokesman Zabiullah Mujahid claimed responsibility in an email sent to the media. He called the bombing the first attack in the spring offensive that Taliban’s leadership said it was starting Sunday.

This year’s offensive is named after Khalid ibn al-Walid, a companion of Islam’s Prophet Muhammad (PBUHU) who became a legendary Muslim military commander known as the ”Drawn Sword of God.”

The insurgents said their forces planned to infiltrate enemy ranks to conduct so-called insider attacks and target military and diplomatic sites with suicide bombers.

Insurgents have escalated attacks recently in a bid to gain power and influence ahead of next year’s presidential election and the planned withdrawal of most US and other foreign combat troops by the end of 2014.

US-backed efforts to try to reconcile the Islamic militant movement with the Afghan government are gaining little traction.

April already has been the deadliest month this year for attacks across the country, where Afghan security forces are increasingly taking the lead on the battlefield in the war that has lasted more than 11 years.

On Saturday, a Nato plane crashed in southern Afghanistan, killing four international troops.

The alliance said initial reports indicated no enemy activity in the area where the plane went down.

Coalition personnel secured the site and were investigating the cause of the crash.

Nato didn’t identify the province where the crash occurred, but Mohammad Jan Rasoulyar, deputy governor of the southern province of Zabul, said an aircraft belonging to foreign forces crashed there on Saturday afternoon.

Nato declined on Sunday to provide any more information about the crash, including the type of aircraft involved, as the investigation continues.

Also on Sunday, the US-led international military coalition said Afghan and foreign forces arrested six insurgents on Saturday, three in Helmand province, one in Baghlan province and two in Kandahar province.

The report said the two taken into custody in Kandahar city included a local Taliban leader who allegedly had coordinated assassinations, sniper ambushes and other attacks there against coalition and Afghan forces.

There are about 100,000 international troops in Afghanistan, including 66,000 Americans. A top priority of the US force, which is slated to drop to about 32,000 by February 2014, is boosting the strength and confidence of Afghan forces.