One person was killed and two others injured in an explosion in downtown of Egypt's capital Cairo on Friday night, weeks before Egypt's upcoming presidential election, official MENA news agency reported. The explosion which was detonated by a car bomb occurred in Ramsis Street in front of the Engineers Syndicate in downtown Cairo, killing the owner of the car, MENA quoted a security source as saying. Egypt's Nile TV said the blast also injured two. Explosive experts are combing the area for possible more bombs in the area. Earlier on Friday at least four people were killed and twelve others injured in three blasts that hit the Egypt's Sinai Peninsula and Cairo. Friday's blasts and protests came as the countdown is ticking for the country's first post-Morsi presidential elections slated for May 26 and 27. Since the ouster of former Islamist President Mohamed Morsi by the army last July, a wave of explosions have targeted security men and their premises in the restive Sinai Peninsula, which have lately extended to hit the capital, the Nile Delta cities and other provinces across the country. A recent official report said the death toll from such attacks has reached nearly 500, most of whom soldiers and policemen. The army has launched a large-scale operation since Morsi's removal to uproot the crime hideouts in the restive Sinai. The al- Qaida-inspired Ansar Bayt al-Maqdis group has claimed responsibility for most of the attacks.