London Underground station staff will stage strikes in the first week of October.
The latest walkout is due to an ongoing dispute over job cuts and working conditions.
The workers will walk out on Wednesday, October 4, and Friday, October 6.
RMT union said this would result in potential disruptions to tube services in the capital.
The union claims RMT’s dispute over cuts will result in hundreds of job losses.
Additionally, increased workloads, greater solitary work, and escalating fatigue levels heighten safety concerns.
Mick Lynch, the general secretary of the RMT, 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 to access the network safely and ensuring that the tube is a safe environment for passengers.”
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He added: “These job cuts and attacks on conditions are going to lead to more unstaffed stations, temporary closures and rising passenger anger.
“Transport for London 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 shut down and we call on mayor Sadiq Khan to meet us urgently to discuss this matter.”
The union said the dispute involves more than 3,500 of its members.