diff --git a/R-package/man/cb.early_stop.Rd b/R-package/man/cb.early_stop.Rd
deleted file mode 100644
index 07e0c4abe..000000000
--- a/R-package/man/cb.early_stop.Rd
+++ /dev/null
@@ -1,64 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/callbacks.R
-\name{cb.early_stop}
-\alias{cb.early_stop}
-\title{Callback closure to activate the early stopping.}
-\usage{
-cb.early_stop(stopping_rounds, maximize = FALSE, metric_name = NULL,
-  verbose = TRUE)
-}
-\arguments{
-\item{stopping_rounds}{The number of rounds with no improvement in 
-the evaluation metric in order to stop the training.}
-
-\item{maximize}{whether to maximize the evaluation metric}
-
-\item{metric_name}{the name of an evaluation column to use as a criteria for early
-stopping. If not set, the last column would be used.
-Let's say the test data in \code{watchlist} was labelled as \code{dtest}, 
-and one wants to use the AUC in test data for early stopping regardless of where 
-it is in the \code{watchlist}, then one of the following would need to be set:
-\code{metric_name='dtest-auc'} or \code{metric_name='dtest_auc'}.
-All dash '-' characters in metric names are considered equivalent to '_'.}
-
-\item{verbose}{whether to print the early stopping information.}
-}
-\description{
-Callback closure to activate the early stopping.
-}
-\details{
-This callback function determines the condition for early stopping 
-by setting the \code{stop_condition = TRUE} flag in its calling frame.
-
-The following additional fields are assigned to the model R object:
-\itemize{
-\item \code{best_score} the evaluation score at the best iteration
-\item \code{best_iteration} at which boosting iteration the best score has occurred (1-based index)
-\item \code{best_ntreelimit} to use with the \code{ntreelimit} parameter in \code{predict}.
-   It differs from \code{best_iteration} in multiclass or random forest settings.
-}
-
-The Same values are also stored as xgb-attributes, however:
-\itemize{
-\item \code{best_iteration} is stored as a 0-based iteration index (for interoperability of binary models)
-\item \code{best_msg} message string is also stored.
-}
-
-At least one data element is required in the evaluation watchlist for early stopping to work.
-
-Callback function expects the following values to be set in its calling frame:
-\code{stop_condition},
-\code{bst_evaluation},
-\code{rank},
-\code{bst} or \code{bst_folds},
-\code{iteration},
-\code{begin_iteration},
-\code{end_iteration},
-\code{num_parallel_tree},
-\code{num_class}.
-}
-\seealso{
-\code{\link{callbacks}},
-\code{\link{xgb.attr}}
-}
-
diff --git a/R-package/man/cb.log_evaluation.Rd b/R-package/man/cb.log_evaluation.Rd
deleted file mode 100644
index 3bfd2fcdb..000000000
--- a/R-package/man/cb.log_evaluation.Rd
+++ /dev/null
@@ -1,32 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/callbacks.R
-\name{cb.log_evaluation}
-\alias{cb.log_evaluation}
-\title{Callback closure for logging the evaluation history}
-\usage{
-cb.log_evaluation()
-}
-\description{
-Callback closure for logging the evaluation history
-}
-\details{
-This callback function appends the current iteration evaluation results \code{bst_evaluation}
-available in the calling parent frame to the \code{evaluation_log} list in a calling frame.
-
-The finalizer callback (called with \code{finalize = TURE} in the end) converts 
-the \code{evaluation_log} list into a final data.table.
-
-The iteration evaluation result \code{bst_evaluation} must be a named numeric vector. 
-
-Note: in the column names of the final data.table, the dash '-' character is replaced with 
-the underscore '_' in order to make the column names more like regular R identifiers.
-
-Callback function expects the following values to be set in its calling frame:
-\code{evaluation_log},
-\code{bst_evaluation},
-\code{iteration}.
-}
-\seealso{
-\code{\link{callbacks}}
-}
-
diff --git a/R-package/man/cb.print_evaluation.Rd b/R-package/man/cb.print_evaluation.Rd
deleted file mode 100644
index cf865bdbf..000000000
--- a/R-package/man/cb.print_evaluation.Rd
+++ /dev/null
@@ -1,28 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/callbacks.R
-\name{cb.print_evaluation}
-\alias{cb.print_evaluation}
-\title{Callback closure for printing the result of evaluation}
-\usage{
-cb.print_evaluation(period = 1)
-}
-\arguments{
-\item{period}{results would be printed every number of periods}
-}
-\description{
-Callback closure for printing the result of evaluation
-}
-\details{
-The callback function prints the result of evaluation at every \code{period} iterations.
-The initial and the last iteration's evaluations are always printed.
-
-Callback function expects the following values to be set in its calling frame:
-\code{bst_evaluation} (also \code{bst_evaluation_err} when available),
-\code{iteration},
-\code{begin_iteration},
-\code{end_iteration}.
-}
-\seealso{
-\code{\link{callbacks}}
-}
-
diff --git a/R-package/man/cb.reset_parameters.Rd b/R-package/man/cb.reset_parameters.Rd
deleted file mode 100644
index 0dfb81623..000000000
--- a/R-package/man/cb.reset_parameters.Rd
+++ /dev/null
@@ -1,37 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/callbacks.R
-\name{cb.reset_parameters}
-\alias{cb.reset_parameters}
-\title{Callback closure for restetting the booster's parameters at each iteration.}
-\usage{
-cb.reset_parameters(new_params)
-}
-\arguments{
-\item{new_params}{a list where each element corresponds to a parameter that needs to be reset.
-Each element's value must be either a vector of values of length \code{nrounds} 
-to be set at each iteration, 
-or a function of two parameters \code{learning_rates(iteration, nrounds)} 
-which returns a new parameter value by using the current iteration number 
-and the total number of boosting rounds.}
-}
-\description{
-Callback closure for restetting the booster's parameters at each iteration.
-}
-\details{
-This is a "pre-iteration" callback function used to reset booster's parameters
-at the beginning of each iteration.
-
-Note that when training is resumed from some previous model, and a function is used to 
-reset a parameter value, the \code{nround} argument in this function would be the 
-the number of boosting rounds in the current training.
-
-Callback function expects the following values to be set in its calling frame:
-\code{bst} or \code{bst_folds},
-\code{iteration},
-\code{begin_iteration},
-\code{end_iteration}.
-}
-\seealso{
-\code{\link{callbacks}}
-}
-
diff --git a/R-package/man/cb.save_model.Rd b/R-package/man/cb.save_model.Rd
deleted file mode 100644
index 9d8059d6d..000000000
--- a/R-package/man/cb.save_model.Rd
+++ /dev/null
@@ -1,34 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/callbacks.R
-\name{cb.save_model}
-\alias{cb.save_model}
-\title{Callback closure for saving a model file.}
-\usage{
-cb.save_model(save_period = 0, save_name = "xgboost.model")
-}
-\arguments{
-\item{save_period}{save the model to disk after every 
-\code{save_period} iterations; 0 means save the model at the end.}
-
-\item{save_name}{the name or path for the saved model file.
-It can contain a \code{\link[base]{sprintf}} formatting specifier 
-to include the integer iteration number in the file name.
-E.g., with \code{save_name} = 'xgboost_%04d.model', 
-the file saved at iteration 50 would be named "xgboost_0050.model".}
-}
-\description{
-Callback closure for saving a model file.
-}
-\details{
-This callback function allows to save an xgb-model file, either periodically after each \code{save_period}'s or at the end.
-
-Callback function expects the following values to be set in its calling frame:
-\code{bst},
-\code{iteration},
-\code{begin_iteration},
-\code{end_iteration}.
-}
-\seealso{
-\code{\link{callbacks}}
-}
-