Syrian forces killed at least 54 people Friday as they sought to quell demonstrations against President Bashar al-Assad before a peace mission by U.N.-Arab League envoy Kofi Annan, opposition activists said.

Tank rounds and mortar shells crashed into opposition districts in the rebellious central city of Homs, killing 17 people, activists said, while 24 were killed in the northern province of Idlib and more deaths were reported elsewhere.

“Thirty tanks entered my neighborhood at seven this morning, and they are using their cannons to fire on houses,” said Karam Abu Rabea, a resident in Homs’s Karm al-Zeitoun neighborhood.

One focus of demonstrations was the anniversary of Kurdish unrest in Syria in 2004, in which about 30 people were killed.

Many thousands of Kurds demonstrated in northeastern cities, YouTube footage showed, some carrying banners that read “Save the Syrian people.” Other clips showed hundreds of protesters in the Assali district of the capital, Damascus.

Syria’s state news agency SANA reported large pro-Assad demonstrations in Damascus and Hassaka in the northeast.

Tight media restrictions imposed by the authorities make it hard to assess conflicting accounts of events on the ground.

U.N. humanitarian chief Valerie Amos, who visited Homs this week, said Assad’s government had agreed to join U.N. agencies in a “limited assessment” of civilian needs in Syria but had not met her request for unhindered access for aid groups.

Syrian officials had asked for more time, she told a news conference in Ankara after visiting Syrian refugees arriving in growing numbers in border camps in Turkey.

Amos said she was “devastated” at the scenes of destruction she saw in Homs and that she wanted to know the fate of civilians who had lived in the city’s Baba Amr district, which rebel fighters left March 1 after a 26-day siege.

Annan, who is to begin his peace mission in Damascus on Saturday, has called for a negotiated political solution, but dissidents say there is no room for dialogue amid Assad’s crackdown.

Rifts among big powers have blocked any U.N. action to resolve the crisis, with China and Russia firmly opposing any measure that might lead to Libya-style military intervention.

China, which sent an envoy to Syria this week, said Friday that it would send an assistant foreign minister to the Middle East and to France to discuss a way forward. It urged Annan to “push for all sides in Syria to end their violence and start the process of peace talks.”

— Reuters