Two former bitter political rivals in Kenya facing trial at the International Criminal Court, Uhuru Kenyatta and William Ruto, have formed an alliance for next year's election.The announcement comes two days before a court in Kenya is due to hear a petition seeking to bar them from contesting the election.Both men deny playing key roles in the violence which followed the 2007 poll.Some 1,200 people were killed and 300,000 forced from their homes.Deputy Prime Minister Kenyatta and Mr Ruto, a former minister, were on opposite sides in the 2007 election.Mr Kenyatta backed President Mwai Kibaki, while Mr Ruto was part of Raila Odinga's alliance seeking to oust the president.The goals of their alliance would be "national unity, prosperity for all Kenyans [and] reconciliation," according to a statement from the office of Deputy Prime Minister Kenyatta.Both men have previously said they would contest the presidential election despite the ICC charges.The statement does not say who will be their presidential candidate in March 2013 - a month before they are due to face trial in The Hague.Further details of the alliance will be announced on Sunday, the statement says.Civil society groups have gone to court, seeking to have the pair banned from the election because of the ICC charges.Under the new 2010 constitution, holders of public office who are charged with a crime must step down.Mr Odinga, who became prime minister under the deal brokered to end the bloodshed, is also expected to contest the presidential election.Mr Kibaki is stepping down next year at the end of his second and final term.