KABUL: Taliban militants are stepping up efforts to destabilise Afghanistan ahead of next month's presidential vote, kidnapping election workers and executing villagers at random to scare people off voting, officials and campaigners said.

The attacks follow the Taliban's warning on Monday that it would use its “full force” against anyone who takes part in the electoral process.

The ballot is due to take place on April 5, and marks the first time in Afghanistan's history that power will be handed from one democratically elected government to another. President Hamid Karzai is constitutionally barred from running for a third term.

On Thursday, police and elders rushed to negotiate the release of four election workers kidnapped by the Taliban in eastern Nangarhar province a day earlier, Afghan officials said.

“Police, elders, everyone is working to ensure a safe release for them,” Ministry of Interior spokesman Sediq Sediqqi said.

The kidnapped election workers were abducted after they left a workshop without notifying security, Sediqqi said.

“These are very difficult times. When members of the Independent Election Commission ... do something without notifying the police, things like this will unfortunately happen,” he said.

Elsewhere, in northern Faryab province, three elders were shot dead by militants as they left a public ceremony on Wednesday.

“They killed them to threaten the rest,” said Mujib Rahman Rahimi, spokesman for front-running presidential candidate Abdullah Abdullah. “They said they would cut off their hands if they vote.”

The attacks against election workers and villagers come at a time of heightened anxiety in the capital, where a little-known militant group shot dead a Western journalist in broad daylight in one of Kabul's most heavily fortified areas this week.

Diplomats warned the incident could signal the start of a sinister new trend in which foreigners were picked off at random in streets - a development that could further complicate support to Afghan institutions during the election.