CAIRO, Nov. 28 (Xinhua) -- A heavy sound of explosion was heard on Friday afternoon around Ramses Hilton hotel near Tahrir Square in downtown Cairo, Xinhua correspondent at Tahrir reported.
Meanwhile, the Egyptian state TV said that the police arrested an unknown person who was riding a bike and threw a sound bomb from a nearby bridge that resulted in no casualties.
On the other hand, Xinhua photographer at Cairo's Matariya neighborhood reported earlier that two people were shot dead during clashes between policemen and protestors.
Earlier in the day, an Egyptian army senior officer was gunned down in drive-by shooting attack by unidentified assailants in Cairo's Nasr City neighborhood.
Egypt's army and police have taken high security measures and deployed across the country's main squares and government buildings due to the calls for holding massive anti-government protests on Friday by the ultraconservative Islamist group Salafists Front.
Supporters of ousted Islamist President Mohamed Morsi planned large anti-government protests on Friday across the country, while the Interior Ministry has been intensifying security nationwide in response.