Police negotiators were talking to a woman while armed police and Army bomb disposal experts stood ready in a stand-off in a seaside town tonight.
Officers were called to Saltburn-by-the-Sea near Redcar, Cleveland, shortly after 11am after concerns were raised about a woman in the area.
Cleveland Police said it was thought she had suspicious items with her and "concerns were raised for her welfare".
She was traced to the seafront and armed police cordoned the area off, closing nearby roads.
A Cleveland Police spokeswoman said: "Armed officers and trained negotiators are currently at the scene as well as other emergency services.
"Specialist officers from the Army bomb disposal unit are also in attendance."
The spokeswoman said some people had been evacuated from nearby premises.
"The priority of the police is to bring about a safe conclusion to the incident and inquiries are ongoing," she said.