PKR de facto leader Anwar Ibrahim's second letter is a private letter that should not be made an issue, Selangor Menteri Besar Azmin Ali said.

"Apparently, that was the personal letter to (PKR vice-president) Shamsul Iskandar (Md Akin)," he said at a walkabout in Kuala Kangsar.

He added that the letter, which was a private communication between both leaders, should not have entered the public domain.

The leaders in PKR get advice and communicate with Anwar, he said.

"I do not think there should be any issue," he said.

He, however, said he was not privy to the letter.

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

This time the letter was reportedly addressed directly to Shamsul, advising him to exercise wisdom and restraint when dealing with Mahathir.

Previously, Anwar in his first letter had warned all PKR leaders to be cautious of working with Mahathir.

The PKR de facto leader had lamented that some party leaders were in cahoots with Mahathir and former finance minister Daim Zainuddin who were elitists and staunch defenders of cronyism.

He warned that working with them could derail PKR's struggles.

He also lamented that while Azmin, PKR vice-president Tian Chua, and PKR secretary-general Rafizi Ramli were authorised to negotiate on the Citizens' Declaration, it had turned out to be a flawed Mahathir document.

The Citizens’ Declaration aims to remove Prime Minister Najib Abdul Razak from power.

Anwar is currently serving a five-year prison sentence for a sodomy conviction, which he claimed was based on a fabricated charge by his political rivals.

The authorities, however, have denied this.

On the arrest of former PKR Kapar MP S Manickavasagam for alleged corruption, Azmin said let the authority carry out its investigation.

The former MP was picked up by MACC officers on Wednesday and released on bail the next day.

Manickavasagam was being probed for allegedly taking bribe from a contractor as inducement to secure a public amenities tender.