UN Secretary-General Ban Ki-moon on Friday condemned a suicide attack that targeted a Shia mosque in eastern Saudi Arabia."Ban stresses that such attacks on places of worship are abhorrent and intended to promote sectarian conflict," his spokesman Farhan Haq told reporters in New York.At least 20 people were killed earlier Friday when a suicide bomber blew himself up inside a Shia mosque in the province of Qatif, according to Saudi media reports.The UN chief said he hoped the perpetrators will be swiftly brought to justice.Friday's attack was the first to target the predominantly Shia eastern part of the country under King Salman bin Abdulaziz, who came to power in January.Several other people were injured-some critically-by the blast. Survivors, meanwhile, said the mosque was full of worshippers when the bombing took place.