Transactions in multi threaded environment in SQLite WP 8.1

I am facing an issue using SQLite with following scenario.

There are two threads working on database.

Both threads have to insert messages in transactions.

So if say one thread commits after inserting 20k rows and other thread has not committed yet.

In output I see all the data has been committed which was inserted by thread 2 till the moment data was committed by thread 1.

Sample function:

    /// <summary>
    /// Inserts list of messages in message table
    /// </summary>
    /// <param name="listMessages"></param>
    /// <returns></returns>
    public bool InsertMessages(IList<MessageBase> listMessages, bool commitTransaction)
    {
        bool success = false;

        if (listMessages == null || listMessages.Count == 0)
            return success;

        DatabaseHelper.BeginTransaction(_sqlLiteConnection);


        foreach (MessageBase message in listMessages)
        {
            using (var statement = _sqlLiteConnection.Prepare(_insertMessageQuery))
            {

                BindMessageData(message, statement);

                SQLiteResult result = statement.Step();
                success = result == SQLiteResult.DONE;


                if (success)
                {
                    Debug.WriteLine("Message inserted suucessfully,messageId:{0}, message:{1}", message.Id, message.Message);
                }
                else
                {
                    Debug.WriteLine("Message failed,Result:{0}, message:{1}", result, message.Message);
                }
            }
        }
        if (commitTransaction)
        {
            Debug.WriteLine("Data committed");
            DatabaseHelper.CommitTransaction(_sqlLiteConnection);
        }
        else
        {
            Debug.WriteLine("Data not committed");
        }

        return success;
    }

Is there any way to prevent commit transaction of thread 2 inserts?