President Vladimir Putin has offered Iran Russian help in dealing with the aftermath of a blast that rocked the Iranian port of Bandar Abbas and has expressed his condolences over the loss of life, the Kremlin said on Sunday.

The blast occurred as Iran began a third round of nuclear talks with the United States in Oman. The cause wasn't immediately clear.

A huge blast probably caused by the explosion of chemical materials killed at least eight people and injured more than 700 on Saturday at Iran's biggest port, Bandar Abbas, Iranian state media reported.