Syrian state media say a bomb has exploded at the state television building in Damascus, wounding several people.

The station remained on the air Monday following the blast, which ripped through the third floor of the building.

A pro-government, private TV station, which itself was hit with a deadly blast in June, broadcast images of the building's damaged walls, wires dangling from a collapsed ceiling and people walking through smoke-filled hallways.

Syrian opposition activists are reporting continued attacks by government forces in the northern city of Aleppo Monday.

The Syrian Observatory for Human Rights says the army is shelling several neighborhoods in Aleppo, and that at least two civilians have been killed.

The country's biggest city has become a key battleground in the uprising against President Bashar al-Assad's rule, as government forces are reported to have massed for what is expected to be a strong offensive against the opposition. Government and opposition claims in Syria are difficult to verify because journalists do not have a freedom of movement.

Meanwhile, U.S. senators John McCain, Joseph Lieberman and Lindsey Graham say the United States should provide direct assistance to the opposition, including weapons, intelligence and training.

In a joint opinion piece published late Sunday by the Washington Post, they say that the U.S. is jeopardizing its national security as well as its moral standing in the world by remaining on the sidelines.

The senators compared not aiding the rebels to the U.S. relationship with Kurds and Shi'ites in Iraq under Saddam Hussein and the Tutsis in Rwanda, saying inaction would haunt the nation “for years to come.”

U.S. Secretary of State Hillary Clinton is expected to visit Turkey Saturday to discuss the deteriorating situation in Syria.