(Reuters) - The U.N. human rights chief accused Syrian President Bashar al-Assad Monday of launching an indiscriminate attack on civilians, emboldened by the failure of the Security Council to condemn him.

U.N. High Commissioner for Human Rights Navi Pillay said the Feb. 4 veto by Russia and China of a draft Security Council resolution condemning the Syrian government and endorsing an Arab League plan for Assad to step aside had only encouraged Damascus to intensify the attacks.

The failure of the Security Council to agree on firm collective action appears to have emboldened the Syrian government to launch an all-out assault in an effort to crush dissent with overwhelming force, Pillay told the 193-nation U.N. General Assembly.

I am particularly appalled by the ongoing onslaught on Homs. ... According to credible accounts, the Syrian army has shelled densely populated neighborhoods of Homs in what appears to be an indiscriminate attack on civilian areas.

An Arab League proposal to boost support for the uprising and to send in foreign peacekeepers has also drawn a guarded response, even as Syrian forces bombarded opposition strongholds.

The central Syrian city of Homs came under army bombardment for a ninth day on Monday, with Syrian forces resuming shelling hours after Pillay's speech, activists said. At least seven people were reported killed on Monday.

The shells are falling at random, activist Hussein Nader said by telephone from Homs.

Mohammad al-Homsi, another activist, said the humanitarian situation was getting worse, describing how three doctors crossed into Baba Amro during a lull in the shelling.

Army roadblocks are increasing around opposition districts but there is a pattern to the bombardment now. It is heavy in the morning, then gives way to an afternoon lull and resumes at night, Homsi said from the city.

Shelling was also reported in the town of Rastan on Tuesday. Reports of action on the ground are difficult to verify because Syria restricts access by journalists.

At the United Nations, diplomats said a draft General Assembly resolution which fully supports the Arab League plan and introduces a call for the appointment of a joint U.N.-Arab League envoy, could be put to a vote later this week.

The resolution, seen by Reuters, is similar to the vetoed Security Council draft, but there are no vetoes in General Assembly votes and its decisions are not legally binding.

The situation on the ground is unbearable, the Qatari president of the General Assembly, Nassir Abdulaziz al-Nasser, told Al Jazeera Television. There is an idea for an Arab draft resolution, which I think will be distributed to the member countries today or tomorrow and will be voted on this week.

He added: The time has come for the United Nations ... to look at the situation seriously either at the Security Council or the General Assembly.

WEIGHING NEXT MOVE

World powers meanwhile digested Arab League proposals calling for a joint U.N.-Arab peacekeeping force for Syria.

The United States and Europe are reluctant to get dragged in militarily. Given Syria's position in the Middle East's religious, ethnic and political faultlines, they fear this would be more risky and complicated than the NATO-led air support that helped Libyan rebels oust Muammar Gaddafi last year.

U.S. Secretary of State Hillary Clinton said in Washington that the peacekeeper proposal would be tough to get through given Russian and Chinese support for Damascus.

There are a lot of challenges to be discussed as to how to put into effect all of their recommendations and certainly the peacekeeping request is one that will take agreement and consensus, Clinton said.

Russia, Assad's close ally and main arms supplier, said it could not support a peacekeeping mission unless both sides ceased the violence first.

China however backed what it termed the Arab League's mediation but offered no clear sign of support for the call.

Relevant moves by the United Nations should be conducive towards lessening tension in Syria ... rather than complicating things, Chinese Foreign Ministry spokesman Liu Weimin said.

Clinton and China's top diplomat Dai Bingguo earlier discussed Syria in a phone call, China's Foreign Ministry said.

British Foreign Secretary William Hague said any peacekeepers should come from non-Western nations whereas French Foreign Minister Alain Juppe said: We think that any external military intervention would only make the situation worse...

A peacekeeping mission would in any case require the cooperation of Syria, which dismissed the League's resolution as a hostile act that targets Syria's security and stability.

OVERNIGHT SHELLING

In her speech, Pillay said the Syrian army was implementing a shoot-to-kill policy. Extensive reports of sexual violence, in particular rape, in places of detention, primarily against men and boys, are particularly disturbing, Pillay said.

Activist said the ferocity of the attack on Homs had fuelled public outrage inside Syria, prompting more demonstrations against Assad in the last few days.

YouTube footage showed what appeared to be thousands of people protesting at a street rally in the town of Kernaz in the countryside to the north of the city of Hama. God salutes the Free Syrian Army, they chanted.

In Homs, government troops concentrated their fire on Baba Amro in the south and al-Waer in the west, which borders the Military College, a main assembly point for tanks and government troops, opposition campaigners said.

Activist Hassan said al-Waer, scene of large pro-democracy demonstrations for months, had come under attack in the last several days from pro-Assad militia known as shabbiha.

We heard that the Free Syrian Army has started responding by attacking roadblocks being manned by shabbiha. Communications with al-Waer have been cut off and the sound of shelling can be now heard, Hassan said.

Earlier in the city of Hama, 50 km (30 miles) north of Homs, government forces backed by tanks and armored vehicles killed at least one man when they raided neighborhoods on Sunday near the countryside where the Free Syrian Army has been active.

It is the third day of such incursions, activist Fady al-Jaber said from Hama. They fire heavy machineguns and anti-aircraft guns at random, then they go in and raid houses and arrest dozens of people.

(Additional reporting by Ben Blanchard in Beijing, Steve Gutterman in Moscow, Erika Solomon in Beirut and Louis Charbonneau at the United Nations; Writing by Angus MacSwan; Editing by Maria Golovnina)