U.N. humanitarian chief Valerie Amos will head to Syria soon in an attempt to secure access for aid workers seeking to deliver emergency relief to people trapped in the country's conflict zones, the United Nations said on Wednesday.

U.N. spokesman Eduardo del Buey said U.N. Secretary-General Ban Ki-moon would dispatch Amos to Syria to assess the humanitarian situation and renew the call for urgent humanitarian access. He said there was no date set for her trip.

We expect the Syrian government to respond positively, he said.

It appears that Amos' visit to Syria already has the blessing of Russia.

Russian foreign ministry spokesman Alexander Lukashevich said Russia has asked Ban to send a representative to liaise with all sides for the safe transit of aid convoys.

Russia and China have twice vetoed U.N. Security Council resolutions condemning Syria for its 11-month crackdown on pro-democracy protesters across the country.

The news of Amos' plans to visit to Damascus came as Syrian President Bashar al-Assad's forces rained rockets and bombs down on opposition-held neighbourhoods in the city of Homs, reducing buildings to rubble and killing more than 80 people, including two Western journalists.

Officials at the world body say that they are increasingly worried about a humanitarian disaster in Syria.

The barrages in Homs marked an intensification of a nearly three-week offensive to crush resistance in the city, one of the focal points of a nationwide uprising against Assad's 11-year rule. Its ferocity has caused international outrage.

The United Nations says that at least 5,400 civilians have died in the uprising against Assad.

(Reporting By Louis Charbonneau; Editing by Will Dunham)