The notice, sent yesterday, said Rehman accused Khan of being a Jewish agent in a TV interview on August 3. He also alleged that Khan has a foreign agenda backed by the Jewish lobby, the media reported today.
Rehman allegedly tried to gain undue political advantage over Khan and his Pakistan Tehrik-e-Insaf party, so he was liable to be proceeded against for defamation under civil and criminal laws, according to the notice.
Khan asked Rehman to apologise unconditionally or to take back his statement within a week of receipt of the notice or face a lawsuit for defamation.
Khan had said on August 5 that he would move court against Rehman.
Rehman's spokesman said his party would respond to the notice after receiving it. He said Rehman would never apologise and the party was ready to prove that Khan had links with the Jewish lobby.