Thad Allen says BP oil well plug 'a work in progress'

The US government's BP oil spill incident commander Adm Thad Allen has said that a permanent plug to "kill" the blown out well is "a work in progress".

Scientists had been analysing tests to see if mud and cement pumped in the top of the well had "killed" it.

Adm Allen said that "everybody is in agreement we need to proceed with the relief well" but drilling would not proceed until they were sure it was safe to do so.