Israel pounded Tehran with fresh strikes and Iran targeted Kurdish guerilla groups in Iraq on Thursday as a spiralling war in the Middle East engulfed the entire region.

A conflict ignited Saturday with US-Israeli attacks that killed Iran's supreme leader Ayatollah Ali Khamenei has spread rapidly, snarling global shipping and energy markets, and sowing panic and chaos in previously safe-haven Gulf nations.

In Lebanon, AFPTV images showed buildings in rubble and plumes of black smokes drifting over Beirut after Israeli strikes aimed at Iran-backed militant group Hezbollah.

AFP reporters in Tehran heard fighter jets screaming across the skies in the west of the city and several explosions as Israel launched a fresh barrage.

Earlier Thursday, Tehran said it had hit Iraq-based Kurdish groups, as the United States reportedly seeks to arm Iranian Kurdish guerillas to infiltrate Iran.

The strikes which killed a member of an exiled Iranian Kurdish group, according to a representative, followed a warning from Iranian officials.