diff --git a/CHANGELOG b/CHANGELOG
index df2f091..01858d7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+0.23.4
+ - enh: run set_num_interop_threads(1) for torchmpo segmenter
 0.23.3
  - fix: ignore non-file-type-like basins
  - fix: workaround for slow reading from HDF5 (don't use index arrays)
diff --git a/src/dcnum/segm/segm_torch/segm_torch_mpo.py b/src/dcnum/segm/segm_torch/segm_torch_mpo.py
index 768bc29..10e3714 100644
--- a/src/dcnum/segm/segm_torch/segm_torch_mpo.py
+++ b/src/dcnum/segm/segm_torch/segm_torch_mpo.py
@@ -37,6 +37,7 @@ def segment_algorithm(image, *,
         # all the multiprocessing.
         # https://pytorch.org/docs/stable/generated/torch.set_num_threads.html#torch.set_num_threads
         torch.set_num_threads(1)
+        torch.set_num_interop_threads(1)
         device = torch.device("cpu")
 
         # Load model and metadata