There were no immediate reports of casualties.
"At 4 am (0100 GMT) they attacked with artillery the villages of Kani Saif, Jomarasi and Kara Sozi, that belong to the Panjwin district," a senior Iraqi border guard official told AFP on condition of anonymity.
"After the (initial) attacks, at 9 am three Iranian helicopters attacked these areas again," he said. "This is the first time they have used helicopters."
The official said the area was not considered a stronghold of the Party of Free Life of Kurdistan (PJAK), an Iranian Kurdish separatist group that appeared to have been the target of the raid.
He said the fighters tend to operate near the village Qalat Dizah further north and that the Panjwin area has only been shelled twice in the past year, much less than areas closer to Iraqi Kurdistan's borders.
The raids came a week after 26 people were killed in a fierce gunbattle between Iranian police and Kurdish rebels near the Iraqi border, but it was not immediately clear if the events were linked.
Eighteen of those killed in the April 24 clash were Iranian policemen and eight were PJAK fighters, Iranian provincial justice chief Allahyar Malekshahi said on Saturday.
"Five people suspected of participating in this terrorist attack have been arrested and are under investigation," he said.
Western Iran, which has a sizeable Kurdish population, has seen deadly fighting in recent years between Iranian security forces and PJAK rebels operating out of rear-bases in neighbouring Iraq.
The group is closely allied with the Turkish Kurdish rebel group, the Kurdistan Workers' Party (PKK).
Blacklisted as a terror group by the European Union and the United States, the PKK took up arms for self-rule in Turkey's Kurdish-majority southeast in 1984, triggering a conflict that has claimed some 44,000 lives.
PKK rear-bases in border districts of northern Iraq were the target of repeated attack by the Turkish and Iranian militaries in December and January and more recently in March and April.
Iraq, Iran, Syria and Turkey all have significant ethnic Kurdish minorities.
Under executed president Saddam Hussein's Sunni-led regime, Tehran and Baghdad fought a devastating 1980-1988 war in which around one million people died.
Relations between Baghdad and Teheran have warmed considerably since the 2003 overthrow of Saddam by US-led forces, although many of Iraq's Sunni Arabs continue to eye Iran with suspicion.
