Samsung Electronics' nightmare is not over. The company announced Monday that it was cutting production of its Galaxy Note 7 smartphones to investigate recent explosions from the latest model that replaced malfunctioning ones.

Samsung says it still does not know what the problem is. "We are temporarily adjusting the Galaxy Note 7 production schedule in order to take further steps to ensure quality and safety matters," Samsung said in a public disclosure to the Korea Exchange.

Analysts questioned Samsung's earlier explanation that faulty batteries caused the phones to catch fire. Some suggested that problematic chips or printed circuit boards might have caused the fires.

The announcement came a day after U.S. telecom companies, such as AT&T, Verizon Communication and T-Mobile, said they would stop replacing Note 7 smartphones. Samsung had recalled 2.5 million Note 7s globally late August in response to the fires.

Samsung Electronics shares fell 1.52% to 1,680,000 won on the KOSPI on Monday, after hitting a record-high of 1,706,000 won on Friday.

Analysts said that Samsung could give up the Note 7 model as it had failed to calm market worries.

"Now, it seems that the scandal will not be resolved easily," said an analyst at a global brokerage house who did not want to be named. "It is a possible scenario that the company scraps the model, giving up this cycle."