iOS retweet with SLRequest returns bad URL error

I'm implementing a retweet functionality but I keep getting a bad URL error after my POST. Here's my code:

SLRequest *twitterRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodPOST URL:[NSURL URLWithString:@"https://api.twitter.com/1.1/statuses/retweet/%@.json"] parameters:[NSDictionary dictionaryWithObject:tweetId forKey:@"id"]];

[twitterRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
  dispatch_async(dispatch_get_main_queue(), ^{

    if ([urlResponse statusCode] == 429) {
        NSLog(@"Rate limit reached");
        return;
    }

    if (error) {
        NSLog(@"Error: %@", error.localizedDescription);
        return;
    }

  });
}];

Any ideas? Am I missing anything? Thanks!

My bad. I forgot to pass the string when creating the request "...%@.json".

i.e.

SLRequest *twitterRequest = [SLRequest requestForServiceType:SLServiceTypeTwitter requestMethod:SLRequestMethodPOST URL:[NSURL URLWithString:[NSString stringWithFormat:@"https://api.twitter.com/1.1/statuses/retweet/%@.json",@"490794578250059776"]] parameters:nil];