Thousands of London Underground workers are to strike on October 4 and 6 in a long-running dispute over jobs and conditions, the RMT union has announced.
The industrial action on October 4 coincides with a planned strike by Aslef members and with the end of the Tory party conference in Manchester.
The union has been locked in a row over cuts it claims will lead to hundreds of job losses.
Safety concerns have also been raised over higher workloads, more lone working and increased fatigue.
RMT boss 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.”
The union said more than 3,500 of its members are involved in the dispute.
