How to connect the audio to bluetooth when playing using AVPlayer

I am playing the audio from an url using AVPlayer, but when the iPhone is connected to a Bluetooth device it is not playing is Bluetooth, how to play via Bluetooth if it is connected, i see some posts in SO, but none of those are clearly explained. Below is my code.

    -(void)playselectedsong{

    AVPlayer *player = [[AVPlayer alloc]initWithURL:[NSURL URLWithString:urlString]];
    self.songPlayer = player;
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(playerItemDidReachEnd:)
                                                 name:AVPlayerItemDidPlayToEndTimeNotification
                                               object:[songPlayer currentItem]];
    [self.songPlayer addObserver:self forKeyPath:@"status" options:0 context:nil];
    [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(updateProgress:) userInfo:nil repeats:YES];

    [self.songPlayer play];

}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

    if (object == songPlayer && [keyPath isEqualToString:@"status"]) {
        if (songPlayer.status == AVPlayerStatusFailed) {
            NSLog(@"AVPlayer Failed");

        } else if (songPlayer.status == AVPlayerStatusReadyToPlay) {
            NSLog(@"AVPlayerStatusReadyToPlay");


        } else if (songPlayer.status == AVPlayerItemStatusUnknown) {
            NSLog(@"AVPlayer Unknown");

        }
    }
}

- (void)playerItemDidReachEnd:(NSNotification *)notification {

 //  code here to play next sound file

}