The Fire Brigades Union is claiming job cuts will be made in Coventry and Birmingham.
It says 18 posts will be made redundant in Coventry, with two traditional fire engines being taken off the road and replaced by one smaller vehicle.
A further 16 firefighters will lose their jobs at stations in Birmingham, with another two fire engines decommissioned, also to be replaced with smaller fire vehicles.
A statement from West Midlands Fire Service is expected at some time this morning.
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