Hundreds of Pakistanis protesting an anti-Islam video produced in the United States have clashed with police as they tried to march toward the U.S. Consulate in the southern city of Karachi.

Police fired tear gas and water cannon at the demonstrators Sunday as they approached the heavily guarded consulate.

Karachi police chief Iqbal Mehmood said the clashes left eight people injured. The rally was organized by a Shi'ite Muslim religious group.

In the Pakistani city of Lahore, about 5,000 people protested against the film. Peaceful demonstrations were held in several other cities in Pakistan, where the protest actions were generally small compared to previous bouts of unrest.

Although demonstrations in other Muslim countries that peaked on Friday have largely subsided, a small group of activists burned an American flag outside the U.S. Embassy in the Turkish capital Ankara on Sunday.

Western embassies across the Muslim world remain on high alert.

U.S. Defense Secretary Leon Panetta said Sunday the turmoil raging across the Muslim world is likely to continue into the days ahead, but that the violence expected by the U.S. appears to be leveling off.

Meanwhile, the president of Libya's National Assembly told CBS News that about 50 people have been arrested in connection with the attack on the U.S. Consulate in Benghazi, which he said was planned by foreigners linked to al-Qaida.

Mohamed Magarief said there was little doubt the assault was planned rather than a spontaneous reaction to the video, citing the fact that it came on the 11th anniversary of the September 11, 2001 attacks against the United States.

But the U.S. ambassador to the United Nations, Susan Rice, said that preliminary information indicated the consulate attack was not pre-meditated.

She said last week's assault began with a “spontaneous” protest over the anti-Islamic video, which followed similar demonstrations in Egypt, where the U.S. embassy was stormed.

Rice told ABC News that Washington believed a small number of people came to the consulate “to replicate the sort of challenge that was posed in Cairo.”

She said that as the event unfolded, “it seems to have been hijacked…by some individual clusters of extremists who came with heavier weapons. And it then evolved from there.”

U.S. Ambassador to Libya Christopher Stevens was killed in the attack along with three other Americans. Several demonstrators have died since then.

The State Department Saturday ordered the departure of all non-essential personnel and the families of diplomats from its embassies in Sudan and Tunisia. The order also warned U.S. citizens against travel to the two countries because of concerns about rising anti-American violence.

The man allegedly behind the obscure, private film was questioned Saturday by U.S. authorities in California.