Scailex, the Israeli importer of Samsung products, has said there are issues with batteries in the popular Galaxy S4 smartphones, with some of them bursting into flames.

According to Israel’s Yedioth Ahronoth newspaper, thousands of the batteries powering the device had been swelling, with about 20 of them ultimately bursting into flames.

In a statement to Tel Aviv Stock Exchange, Scailex said that since the third quarter of 2013, the company started receiving complains about the problems, and the issue is currently being examined.

"The company was in constant and intensive contact with Samsung on the issue of these problems, and in February 2014 started an independent examination," the Israeli firm added.

Scailex has forwarded the details regarding the problem to Samsung, requesting clarification, though it has not listed out any specific problem.

Samsung told Reuters that the swollen batteries have never been determined as the cause of burning cases.

"However, to ensure a seamless experience for our customers, Samsung has been providing replacements for the swollen batteries free of charge, regardless of the warranty period since October 2013," the South Korean firm noted.

Last October, Samsung offered a free trade-in service on batteries for its Galaxy S4, upon complains concerning batteries being swollen or getting rapidly drained.

Launched in March 2013, the Galaxy S4 has a 2600mAh Lithium-Ion battery, and features an eight-core chip, non-touch gestures to control the screen and an eye-tracking system.