Japanese firm Icom said Thursday that it was investigating after media reported that two-way radio devices bearing its logo exploded in Lebanon.

"Earlier today in worldwide media, there have been reports that two-way radio devices bearing the Icom logo have exploded in Lebanon," the company said in a statement.

"We are currently investigating the facts surrounding this matter. We will release updated information as it becomes available on our website," it added.

In the second wave of device explosions in as many days, 20 people died and more than 450 were wounded on Wednesday in Hezbollah strongholds in Lebanon, officials said.

A source close to Hezbollah said walkie-talkies used by its members blew up in its Beirut stronghold, with state media reporting similar blasts in south and east Lebanon.

They came a day after the simultaneous explosion of hundreds of paging devices used by Hezbollah killed 12 people, including two children, and wounded up to 2,800 others across Lebanon, in an unprecedented attack blamed on Israel.

There was no comment from Israel. The White House warned all sides against "an escalation of any kind".