The bravery of two Sunnis who died trying to stop a suicide bomber killing Shi'ite pilgrims is being praised as a sign that Iraq can overcome sectarian divisions amid its worst political crisis in a year.

Police officer Nizhan al-Jubouri and Ali al-Sabaa, a soldier, died last week when they rushed at a bomber in a crowd at a police checkpoint near the southern city of Nassiriya in a bid to stop his attack, police said.

The bomb killed 44 people and wounded scores as pilgrims flocked to the Shi'ite holy city of Kerbala for the Arbain religious rite, but some people have said the toll could have been worse had it not been for the pair's actions.

The story of selflessness has been the subject of newspaper editorials and chatter across a country where a political dispute has revived concerns about sectarian conflict.

Politicians, government officials and tribal leaders attended their funerals with thousands of Sunnis and Shi'ites.

What happened assured us that there are no more categories such as Shi'ite or Sunni, said Mahmoud Abed, a Shi'ite witness who helped evacuate victims from the scene.

Today, I love Sunnis more than ever.

The two men were charging toward the bomber and were just a couple of metres away when he detonated an explosive vest.

They gave their souls for the sake of duty and did not treat (the situation) on a sectarian basis, Prime Minister Nuri al-Maliki said.

Iraq has been on edge since, shortly after the last U.S. troops left in December, Maliki's Shi'ite-led government tried to arrest Sunni Vice President Tareq al-Hashemi on charges he ran death squads and Maliki asked parliament to oust his Sunni deputy, Saleh al-Mutlaq.

The current political crisis threatens to unravel Iraq's fragile coalition government.

Nassiriya was the bloodiest of a series of bombs targeting Shi'ites that have killed scores of people in recent weeks. Security forces are on high alert this week for more attacks as hundreds of thousands of Shi'ites gather again in Kerbala.

MARTYRS

Nizhan al-Jubouri, from Kirkuk, was married with a child. and Ali al-Sabaa, from Diyala province, left a wife and three children. Both were in their late 20s.

I had two martyred sons and now Ali is the third one, said his father, Ahmed al-Sabaa. Myself, Ali and my tribe, we have all sacrificed for this country, just to prove that there is no difference between Shi'ites and Sunnis.

Sectarian fighting in 2006-07 killed thousands and pushed Iraq to the brink of civil war.

They (the terrorists) want to ignite sedition by killing Shi'ites in Shi'ite areas, to accuse the Sunnis of being behind it, said General Sabah al-Fetlawi, commander of the Dhi Qar province police.

It's their bad luck that the army and police who were on duty in that area included our Sunni brothers.

Maliki promoted each of the men by two ranks posthumously and gave their families apartments and about $25,000 in cash.

General Fetlawi said Jubouri and Sabaa's rush toward the bomber sent a message written in blood: There is no difference between Shi'ite and Sunni.

Some Iraqis were hoping their political leaders would take the message to heart.

This is a message for all the bad politicians that they cannot divide Iraq or take advantage of sectarianism to divide it, said Abdul Razaq al-Batat, a Shi'ite from Sadr City.

(Additional reporting by Mustafa Mahmoud in Kirkuk; Editing by Jim Loney and Richard Meares)