diff --git a/c_api/IndexIVF_c_ex.cpp b/c_api/IndexIVF_c_ex.cpp
index 5b72e15c94..39041a5265 100644
--- a/c_api/IndexIVF_c_ex.cpp
+++ b/c_api/IndexIVF_c_ex.cpp
@@ -31,4 +31,39 @@ int faiss_SearchParametersIVF_new_with_sel(
         *p_sp = reinterpret_cast<FaissSearchParametersIVF*>(sp);
     }
     CATCH_AND_HANDLE
+}
+
+int faiss_Search_closest_eligible_centroids(
+        FaissIndex* index,
+        int n,
+        float* query,
+        int k, 
+        float* centroid_distances,
+        idx_t* centroid_ids) {
+    try {
+        faiss::IndexIVF* index_ivf = reinterpret_cast<IndexIVF*>(index); 
+        assert(index_ivf);
+
+        index_ivf->quantizer->search(n, query, k, centroid_distances, centroid_ids);
+    }
+    CATCH_AND_HANDLE
+}
+
+int faiss_IndexIVF_search_preassigned_with_params(
+        const FaissIndexIVF* index,
+        idx_t n,
+        const float* x,
+        idx_t k,
+        const idx_t* assign,
+        const float* centroid_dis,
+        float* distances,
+        idx_t* labels,
+        int store_pairs,
+        const FaissSearchParametersIVF* params) {
+    try {
+        reinterpret_cast<const IndexIVF*>(index)->search_preassigned(
+                n, x, k, assign, centroid_dis, distances, labels, store_pairs,
+                reinterpret_cast<const faiss::SearchParametersIVF*>(params));
+    }
+    CATCH_AND_HANDLE
 }
\ No newline at end of file
diff --git a/c_api/IndexIVF_c_ex.h b/c_api/IndexIVF_c_ex.h
index e82c5c106f..1aa9378b66 100644
--- a/c_api/IndexIVF_c_ex.h
+++ b/c_api/IndexIVF_c_ex.h
@@ -26,6 +26,47 @@ int faiss_IndexIVF_set_direct_map(
 int faiss_SearchParametersIVF_new_with_sel(
         FaissSearchParametersIVF** p_sp,
         FaissIDSelector* sel);
+/*
+    Return 'k' centroids in the index closest to the query vector.
+
+    @param n: number of queries.
+    @param query: query vector.
+    @param k: count of closest number of vectors.
+    @param centroid_distances: output distances, size n * k.
+    @param centroid_ids: output centroid IDs, size n * k.    
+*/
+int faiss_Search_closest_eligible_centroids(
+        FaissIndex* index,
+        int n,
+        float* query,
+        int k,
+        float* centroid_distances,
+        idx_t* centroid_ids
+);
+
+/*
+    Search the clusters whose IDs are in 'assign' and
+    return the 'k' nearest neighbours from among them.     
+
+    @param n: number of queries.
+    @param x: query vector, size n * d.
+    @param k: count of nearest neighbours to be returned for each query.
+    @param centroid_ids: output centroid IDs, size n * k. 
+    @param distance: output distances, size n * k
+    @param labels: output labels, size n * k
+*/
+int faiss_IndexIVF_search_preassigned_with_params(
+        const FaissIndexIVF* index,
+        idx_t n,
+        const float* x,
+        idx_t k,
+        const idx_t* assign,
+        const float* centroid_dis,
+        float* distances,
+        idx_t* labels,
+        int store_pairs,
+        const FaissSearchParametersIVF* params);
+
 
 #ifdef __cplusplus
 }