Demonstrators and police clashed outside the Interior Ministry in the Egyptian capital late Tuesday in the most intense battle between the two sides in months.

It was unclear whether anyone was killed as fighting continued into Wednesday morning, with police surrounding protesters and the demonstrators throwing molotov cocktails at the policemen to push them back. Dozens were reported injured.

The clashes are a sign of the growing tension between Egyptians seeking reform and the military leadership that took control of the nation after President Hosni Mubarak was ousted in February. Many activists and relatives of the more than 800 people killed during the 18-day popular uprising are angry at what they see as continued human rights violations and a lack of justice.

Human rights groups say that few policemen involved in the killings are being prosecuted, that those being investigated have not been suspended from their jobs and that only one officer has been convicted — in absentia. The protracted trials of top government officials also have angered many Egyptians as more than 7,000 civilians have been convicted in hasty military tribunals since January.

The clashes began after slain protesters’ relatives were barred from a celebration for the families of “martyrs” at a Cairo theater, witnesses said. Security forces beat people and forced them to stay away, videos showed.

The families and demonstrators then walked to the Interior Ministry, seen as a symbol of the repressive and harsh practices of the old regime, to protest and throw rocks. Police were deployed and began shooting birdshot, rubber bullets and tear gas into the crowd, which numbered hundreds, then thousands of people.

Protesters called for the end of military rule, and some screamed, “Now the real revolution begins.’’

By midnight Tuesday, the clashes intensified as police pushed people away from the building and into Tahrir Square, the epicenter of the uprising. The clashes went on for hours, and protesters bled in the square. The Interior Ministry security forces surrounded the square, yelling, “You want the press to see this!” and cursing at the crowd. There was no sign of the military.

“We are not thugs,” said Samer Abdul Razek, 29, who lost a friend Jan. 28 when he was shot in the head by a sniper. Razek, a student of literature, was bleeding from a stomach wound he suffered when hit by a rock thrown by security forces. “I want this government and military rule to end.”

Mansour is a special correspondent.