The U.S. has carried out a wave of drone strikes inside Pakistan over the last three days, with the latest attack on Monday killing between eight and 15 suspected militants in the north-west of the country.

Monday's strike in the Waziristan tribal region follows similar drone launched attacks on Saturday and Sunday, bringing the total number of attacks to seven in less than two weeks.

The latest incursion into Pakistani air space came as Islamabad continues to block U.S. and NATO access to Afghanistan via overland supply routes.