Tube union, RMT will take strike action on London Underground on October 4 and 6 over job losses and safety concerns.
The union has been locked in a long running dispute over 600 station staff cuts and detrimental working conditions since last year.
Safety concerns have also been raised regarding fewer staff facing higher workloads, more lone working and increased fatigue.
The job losses planned will affect every aspect of the tube including stations and maintenance, leading to the likelihood of more unstaffed stations and a lowering of safety standards.
RMT general secretary Mick Lynch said: "Station staff have had enough of having their livelihoods threatened by job losses and attacks on their terms and conditions.
"Station staff have a vital role to play assisting vulnerable passengers access the network safely and ensuring that the tube is a safe environment for passengers.
"These job cuts and attacks on conditions are going to lead to more unstaffed stations, temporary closures and rising passenger anger.
"TfL has had its budgets slashed but the savings made by these station staff cuts will be negatable and will lead to shortages that are unacceptable.
"This strike action will lead to the tube being shutdown and we call on Mayor Sadiq Khan to meet us urgently to discuss this matter."
Notes: In the wake of the Kings Cross fire of 1987, Minimum Staffing Levels were enshrined in statute by the Fire Precautions (Sub-surface Railway Stations) Regulations 1989 (S.I. 1989/1401) and then reinforced by London Underground regulations that set safe staffing levels for stations based on their size and traffic.