By Patrick Werr
CAIRO, June 29 (Reuters) - Police fired teargas in Cairo's central Tahrir Square overnight on Wednesday at several hundred mainly Egyptian youths, some of whom threw stones and demanded that trials of former senior officials proceed more swiftly.
Clashes broke out late on Tuesday in a nearby area of Cairo where families of some of the more than 840 people killed in the uprising that led to Hosni Mubarak's overthrow in February had gathered to honor those killed.
The Interior Ministry blamed a group seeking to disrupt the event and stir up a riot. It was the first such violence in weeks in Tahrir Square, the center of the revolt that led to Mubarak being toppled. Police in riot gear and with shields blocked protesters from marching toward the ministry.
Ambulances workers treated people mostly for inhaling teargas. A Reuters correspondent saw several people with minor wounds, including some with cuts on their heads.
"The people are angry that the court cases against top officials keep getting delayed," Ahmed Abdel Hamid, 26, a bakery employee, said at the scene. He clutched stones in his hands.
He said police clashed with some of those gathered at the event to honor the "martyrs," as those killed in the uprising are called. This prompted protesters to move to Tahrir.
"The people want the fall of the regime," some chanted in Tahrir.
Others called for Field Marshal Mohamed Hussein Tantawi, head of the military council now ruling Egypt, to step down.
The ministry said in a statement that a group of people had been stopped from joining the event at a theater to honor the "martyrs" and had tried to barge their way in, prompting the police to intervene.
The group moved to other areas. Police detained seven people it blamed for stirring up riots, the ministry said.
Political activists who have helped organize other recent protests in Tahrir said the angry scenes on Tuesday evening and early Wednesday were not part of any planned protest.
Egypt's former interior minister, Habib al-Adli, has been sentenced to jail for corruption but he and other officials are still being tried on charges related to killing protesters. Police vehicles were stoned by protesters at Sunday's hearing.
Police used batons, teargas, water cannon and live ammunition against protesters in the first days of the 18-day uprising before they were ordered off the streets and the army moved in. Mubarak then handed power to an army council.
The former president, now hospitalized, has also been charged with killing protesters and could face the death penalty. Mubarak's trial starts on August 3.
(Writing by Edmund Blair; Editing by Angus MacSwan)