Samsung Electronics Co. has begun the U.S. exchange program for the Galaxy Note 7 smartphones amid concern over a battery problem, the local sales arm of the South Korean tech giant said.

On Friday, Samsung announced its findings that some of the new devices that went on sale two weeks ago caught fire due to a "battery cell issue."

Samsung announced a global recall of all Galaxy Note 7 phones sold worldwide in a quick and bold response.

"Samsung is taking a proactive approach to address customer needs around the Note 7," Tim Baxter, president of Samsung Electronics America, said in a statement issued on Friday (local time). "We are encouraging customers to exchange their Note 7 by taking advantage of our Product Exchange Program. The safety and satisfaction of our customers is Samsung’s top priority."

There are two options: Customers can replace their current device with a new Galaxy Note 7 or exchange it for a Galaxy S7 or Galaxy S7 edge, plus receive a refund of the price difference.

In what Samsung's U.S. operation arm called a "gesture of appreciation," consumers will also receive a $25 gift card or bill credit.

In a press conference held in Seoul on Friday, Koh Dong-jin, head of Samsung's mobile business division, offered a public apology for the reported fires involving the newly released phones, saying they were found to have been caused by faulty battery cells.

Although only a very small portion of Galaxy Note 7 phones sold has had such a problem, he added, his company made the unprecedented decision to recall all 2.5 million products sold at home and abroad.

It's estimated to cost as much as 1.5 trillion won ($1.3 billion). Samsung officials said they aim to complete the recall by next year, with the possibility of an extension.

"Our provisional goal is to have all the products sold replaced by March next year," an official said. "Depending on proceedings down the road, we may consider extending (the deadline)." (Yonhap)