A senior officer in the Iraqi army, which was manning the checkpoint near the town of Al-Baghdadi in Anbar province, said nine soldiers were also wounded in the morning attack.
He told AFP that after the suicide attacks some 25 jihadists launched an assault on the checkpoint, the main one on the road leading to Al-Asad air base, where a large number of Iraqi troops and foreign advisers are stationed.
The officer said most of the gunmen were wearing suicide vests.
Malallah al-Obeidi, the head of the Al-Baghdadi local council, confirmed the details of the attack and said that Iraqi forces were in control of the checkpoint.
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Al-Baghdadi lies on the Euphrates river, about 180 kilometres northwest of Baghdad.
Iraqi security forces have in recent days been involved in a major push to retake the city of Hit, which lies further along the river and is controlled by the Islamic State group.
They are closing in on the town from Al-Baghdadi and from Ramadi, the capital of Anbar province which was fully retaken from IS last month.
"We fear that as many as 50,000 individuals will be displaced in the upcoming days as the military operations continue," said the Norwegian Refugee Council's Programme Manager, Salah Noori.
Aid agencies have warned that the families displaced from Hit and its surroundings are very hard to reach and still dangerously close to the front lines.
Some 53,000 people had already been forced to flee their homes this year before the start of the operation to retake Hit, according to UN figures.