Abu Holman, who said he was outside the tent at the time of the blast, told The Associated Press news agency that al-Qaeda in Iraq was to blame for the attack.
"Al-Qaeda is targeting the Kurds because it believes that we are involved in the political process and collaborating with the Americans. There are still many al-Qaeda hotbeds in our area," he said from hospital.
There was no immediate claim of responsibility.
Diyala is home to a mixed population of Shia Kurds and Sunni Arabs.
Violence has dropped sharply in Iraq in the last year to lows rarely seen since the US-led invasion of 2003, but anti-government fighters have shown themselves still capable of launching devastating attacks.
The blast in Jalawla came after attacks in the western city of Mosul and Baghdad earlier on Monday.
At least eight people were killed and 16 wounded in the capital, Baghdad, when a bomb exploded at a bus terminal in the west of the city.
"An IED [improvised explosive device] went off near a garage where people were gathered to have their cars repaired," a police officer told the AFP news agency.
It was the second attack in the predominantly Sunni Muslim district of Abu Ghraib this month. On March 10, a suicide bomber killed at least 28 people in the area.
In Mosul, two separate bombings wounded four police officers and two civilians on Monday.