diff --git a/ChangeLog b/ChangeLog
index 0565fb6..f3aff0b 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,8 +1,9 @@
-2018-09-19
+2018-09-21
 
         * Version 1.6.0 released
         ========================
 
+        Add ctbkgcube::cntcube() method (#2685)
         Avoid ctselect error in case that RoI radius is unchanged (#2682)
         Add "use_irf_bkg" parameter to cslightcrv
         Add "like_accuracy" parameter to likelihood tools and scripts (#2662)
diff --git a/NEWS b/NEWS
index c3cf327..857e0d6 100755
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,6 @@
 New Features and Important Changes in ctools 1.6.0
 
-19 September 2018
+21 September 2018
 
 
 Introduction
@@ -56,7 +56,10 @@ Copy the time reference from the first input observation (#2054).
 
 ctbkgcube - CTA background cube generation
 ------------------------------------------
-None
+Add ctbkgcube::cntcube() method so that a counts cube be specified as
+instance before running the tool. This avoids storing the counts cube on
+disk if the couts cube definition should be used to generate a background
+cube (#2685).
 
 
 ctbutterfly - Generate butterfly diagrams
diff --git a/doc/source/admin/release_history/1.6.rst b/doc/source/admin/release_history/1.6.rst
index 9599542..fc7df6f 100644
--- a/doc/source/admin/release_history/1.6.rst
+++ b/doc/source/admin/release_history/1.6.rst
@@ -34,6 +34,8 @@ Bug fixes
 Improvements
 ------------
 
+* [`2685 <https://cta-redmine.irap.omp.eu/issues/2685>`_] -
+  Add ``ctbkgcube::cntcube()`` method
 * Add ``use_irf_bkg`` parameter to :ref:`cslightcrv`
 * [`2671 <https://cta-redmine.irap.omp.eu/issues/2671>`_] -
   Do not skip bins with zero counts in :ref:`csspec`
diff --git a/pyext/ctbkgcube.i b/pyext/ctbkgcube.i
index ca6b16f..7a431cd 100755
--- a/pyext/ctbkgcube.i
+++ b/pyext/ctbkgcube.i
@@ -1,7 +1,7 @@
 /***************************************************************************
  *               ctbkgcube - Background cube generation tool               *
  * ----------------------------------------------------------------------- *
- *  copyright (C) 2014-2016 by Chia-Chun Lu                                *
+ *  copyright (C) 2014-2018 by Chia-Chun Lu                                *
  * ----------------------------------------------------------------------- *
  *                                                                         *
  *  This program is free software: you can redistribute it and/or modify   *
@@ -48,6 +48,7 @@ public:
     void                      run(void);
     void                      save(void);
     void                      publish(const std::string& name = "");
+    void                      cntcube(const GCTAEventCube& cntcube);
     const GCTACubeBackground& bkgcube(void) const;
     const GModels&            models(void) const;
 };
diff --git a/src/ctbkgcube/ctbkgcube.hpp b/src/ctbkgcube/ctbkgcube.hpp
index bda9778..d8fa505 100755
--- a/src/ctbkgcube/ctbkgcube.hpp
+++ b/src/ctbkgcube/ctbkgcube.hpp
@@ -59,6 +59,7 @@ public:
     void                      run(void);
     void                      save(void);
     void                      publish(const std::string& name = "");
+    void                      cntcube(const GCTAEventCube& cntcube);
     const GCTACubeBackground& bkgcube(void) const;
     const GModels&            models(void) const;
 
@@ -78,12 +79,29 @@ protected:
 
     // Protected members
     GCTACubeBackground m_background;  //!< Background cube
+    GCTAEventCube      m_cube;        //!< Event cube
     GModels            m_bkgmdl;      //!< CTA background models
     GModels            m_outmdl;      //!< Output models
 };
 
 
 /***********************************************************************//**
+ * @brief Set event cube
+ *
+ * @param[in] Event cube.
+ ***************************************************************************/
+inline
+void ctbkgcube::cntcube(const GCTAEventCube& cntcube)
+{
+    // Set counts cube
+    m_cube = cntcube;
+
+    // Return
+    return;
+}
+
+
+/***********************************************************************//**
  * @brief Return background response cube containing background rate
  *
  * @return Background response cube.
@@ -96,7 +114,6 @@ const GCTACubeBackground& ctbkgcube::bkgcube(void) const
 }
 
 
-
 /***********************************************************************//**
  * @brief Return background model container
  *