Union members have voted for industrial action on the London Underground (LU) in a row over jobs and safety.
The Rail Maritime and Transport (RMT) union believes safety on the Tube will be compromised by the 800 job cuts proposed by bosses.
RMT General Secretary Bob Crow said its members would not "sit by while the tracks are turned into a death trap".
But LU's strategy director Richard Parry accused the RMT of "scaremongering".
According to LU 3,727 workers who belong to the RMT, out of a possible 8,700, cast a vote.
The union said 76% of those who voted were in favour of strike action.
It said a date for the strike had not been agreed and it would begin an extensive consultation with members.
The RMT said it would also talk to its sister transport union the TSSA - which is to announce its own ballot result next week - on the next course of action.
Mr Crow said: "RMT members have sent a clear message in this ballot that they will not sit by while the tracks are turned into a death trap and our Tube stations and platforms are left unstaffed."
A Transport for London spokesman said: "The majority of the roughly 800 posts that are identified for reduction are ticket office staff."
LU's Mr Parry said: "The RMT leadership is once again scaremongering.
"There will be no compulsory redundancies, our stations will continue to be staffed at all times while trains are operating.
"All stations with a ticket office will continue to have one. This vote for strike action is unnecessary; any industrial action will simply lose staff pay."