NAIROBI: Kenyan President Mwai Kibaki on Monday convened an emergency meeting of the country's security chiefs following blasts that killed five people during a political rally.The attacks, which also wounded more than 80 people, ripped through a rally in Nairobi campaigning against a proposed constitution due to be submitted to a referendum on August 4."The president has convened an early morning security meeting to discuss this matter, in order to get to the depth of this matter," Vice President Kalonzo Musyoka told reporters."We want to get to the bottom of this matter..., we are appealing for calm from all Kenyans as police investigate the matter," he added.The blasts went off late Sunday during a rally opposing the proposed constitution in the capital's main park.It was the most serious incident in the east African nation since the violence that followed disputed elections in 2007 left 1,500 people dead and 300,000 displaced from their homes.Panic gripped the crowd in Uhuru (Freedom) Park in the heart of the capital when the blasts went off during prayers at the end of the rally, called by evangelical Protestant churches, Nairobi police chief Anthony Kibuchi said."There were two explosions in the middle of the crowd," he said.Police sealed off the vast park as ambulances converged on the scene, then sped away to take the casualties to various hospitals.Several thousand people were attending the rally, where organisers and speakers appealed for calm from the podium.Inside one hospital, some of the bloodstained victims appeared unconscious, lying on stretchers on the floor of the emergency ward. Their injuries were mainly to their legs and lower torsos.It appeared that an explosive device had been thrown at the crowd, police chief Kibuchi said, while survivors thought hand grenades had been used. The blasts were said to have gone off 15 minutes apart.The emergency meeting was due to be attended by the president, Prime Minister Raila Odinga, the ministers of interior and defence, as well as the country's army chief.On August 4, a referendum is due to be held on a new constitution which had been one of the main reforms pledged by Kenya's leaders in the aftermath of the deadly violence sparked by a disputed 2007 election.Although Kenya's once feuding principals openly support the new constitution, their respective parties appear divided, with some politicians concerned over land issues and a clause on abortion.The referendum also comes against the backdrop of an intensifying race for the next presidential election, due in 2012.