Afghan officials said Monday they had arrested three Pakistani men who were allegedly trying to kill Zalmay Khalilzad, the US ambassador to Kabul, during his weekend visit to an eastern Afghan province.

The incident comes amid growing impatience in Kabul with what US and Afghan officials see as Pakistan's failure to stop militants using its territory as a base for attacks. A Kabul official said the men had confessed to plotting to assassinate Mr Khalilzad, but declined to comment further.