A father is believed to be armed with weapons and has his eight-year-old son with him at a home in Coventry.
The 41-year-old has been involved in a stand-off with armed police and other specially trained officers, in the Earlsdon area of the city, began early on Sunday.
Roads and a primary school are closed while armed officers remain in a stand-off with the man in Coventry.
West Midlands Police said it was first called to "conduct a safe and well check on a man and a child" shortly after midnight on Sunday morning (January 9th).
Since then the 999 presence has gradually increased and people have been told to stay in their homes.
A resident living nearby, who did not wish to be named, said he saw the 999 teams as they arrived at the start of the incident.
"I hadn't noticed anything until around noon when I opened our blinds and saw about four or five police cars and a van," they said.
A West Midlands Police spokesperson said: "A cordon remains in place around a house in Earlsdon Avenue North, Coventry this morning where a man has been refusing to come out since the early hours of yesterday morning (9 January).
"The 41-year-old has his eight-year-old son with him and there are some concerns for their safety.
"Several officers, including armed police and other specially trained officers, are at the scene to bring the incident to a safe conclusion.
"Unfortunately, residents, businesses, a school and travel are severely disrupted by the cordon. We’re sorry for the inconvenience, but our priority is the safety of those involved.
"Please avoid the area where possible and we will issue updates on the situation as soon as we can."
Superintendent Pete Henrick said: "We understand that this situation is deeply worrying for some local residents and we want to reassure them that we are doing everything we can to bring it to a safe conclusion.
"I ask that people bear with us as specialist officers remain at the scene."