Umno secretary-general Tengku Adnan Tengku Mansor suspects there might be puppeteers behind the Sepang Umno move against Prime Minister Najib Abdul Razak.

"We will investigate to see if the branch leaders are really behind this or if there are puppeteers," Tengku Adnan told reporters at the Parliament lobby today.

He was asked about the 20 Sepang Umno branch leaders who yesterday called for Najib to step down .

On Oct 13, Teluk Kemang Umno branch leaders also called for Najib to step aside.

"However when we investigated (the Teluk Kemang matter) there were not so many leaders (against Najib).

"There is someone trying to break up Umno," Tengku Adnan said.

Umno has been facing internal strife after Najib axed Muhyiddin Yassin as deputy prime minister in July.

It is believed that Muhyiddin, the Umno deputy president, is one of seven party leaders being investigated for disciplinary infractions.

The leaders may be suspended from their positions and party membership, should the Umno decide to pursue disciplinary action against them.