MIRANSHAH (Agencies) A US drone attack Sunday killed 20 militants in an area of North Waziristan where local Taliban chief Hakimullah Mehsud reportedly escaped death days ago, officials said. The attack took place in Shaktoi area, 40 kilometres southeast of Miranshah, the main town in North Waziristan - the same spot where US missiles pounded an extremist hideout on Thursday. That raid triggered rumours that Mehsud had been killed or injured, but the chief of the Tehreek-e-Taliban Pakistan (TTP) released an audio message late Saturday denying rumours of his demise and vowing revenge for the US strikes. Security officials said US drones appear to be tracking Mehsud amid a surge in the strikes by unmanned spy planes. Sundays deadly bombing was the tenth US drone strike to hit tribal belt this month alone. The target was a militant compound, said a security official in the area. Twenty militant deaths have been confirmed. An intelligence official said that drone aircraft fired at least three missiles, while militants had ringed the demolished compound in the remote and mountainous area and were digging out the bodies. The drones are apparently tracking and targeting Hakimullah Mehsud, whose presence is frequently reported in the area, he said. Another security official, who also asked not to be named because of the sensitivity of the US strikes, said it was too early to tell if any high-value militant targets were among the 20 killed on Sunday. The pilotless drone strikes are a source of friction between the United States and Pakistan, which says they are a violation of its sovereignty. US officials say the missile strikes are carried out under an agreement with Islamabad that allows Pakistani leaders to decry the attacks in public. Islamabad denies this.