Donald Trump Goes on Twitter Tirade Against Paul Ryan and 'Disloyal' Republicans

— -- Republican presidential nominee Donald Trump went on a Twitter tirade against House Speaker Paul Ryan and Republican leaders in general after Ryan in a conference call yesterday with GOP House members told them that he was not rescinding his endorsement of Trump but would not defend or campaign for him.

Ryan also told House members, "You all need to do what's best for you in your district."

Trump blasted Ryan this morning as a "weak and ineffective leader."

Asked to respond to Trump's criticism, a representative from Ryan's office told ABC News, "Paul Ryan is focusing the next month on defeating Democrats, and all Republicans running for office should probably do the same,"

Some Republicans have withdrawn their endorsement of Trump or announced they will not vote for him in November since the release Friday of a 2005 tape in which he is heard making crude comments about women.

ABC News' Benjamin Siegel contributed to this report.