PKR deputy president Azmin Ali is not aware of an alleged second letter from jailed party de facto leader Anwar Ibrahim, again warning PKR against being too close to former PM Dr Mahathir Mohamad.

"I'm not sure because I haven't seen it," Azmin told reporters when met in Sungai Besar today.

The Star today cited a source as saying Anwar had issued a second letter from behind bars.

This time the letter was reportedly addressed directly to PKR vice president Shamsul Iskandar Md Akin, advising him to exercise wisdom and restraint when dealing with Mahathir.