The United Nations human rights chief Wednesday condemned the reported repeated use of cluster munitions and heavy weaponry by Libyan Government forces against civilians in Misrata, warning that such acts could constitute international crimes.

"I urge the Libyan authorities to face the reality that they are digging themselves and the Libyan population deeper and deeper into the quagmire. They must halt the siege of Misrata and allow aid and medical care to reach the victims of the conflict," said UN High Commissioner for Human Rights Navi Pillay.

Misrata, a north-western city with an estimated population of 300,000 people, has been the scene of continuous fighting since earlier this year between military forces allied to the regime of Muammar al-Qaddafi and opposition groups.

"Since the city is largely cut off, it is not known precisely how many civilians have died or been injured during two months of fighting there, but it is clear that the numbers are now substantial, and that the dead include women and children," Ms. Pillay said in a news release.

"Using imprecise weaponry such as cluster munitions, multiple rocket launchers and mortars, and other forms of heavy weaponry, in crowded urban areas will inevitably lead to civilian casualties," she noted, adding that there are also reports of snipers deliberately targeting civilians in Misrata and other places in Libya.

"The pro-Government forces besieging the city, including their commanders and all other personnel, should be aware that – with the International Criminal Court investigating possible crimes – their orders and actions will be subject to intense scrutiny," stated Ms. Pillay.

"Under international law, the deliberate targeting of medical facilities is a war crime, and the deliberate targeting or reckless endangerment of civilians may also amount to serious violations of international human rights law or international humanitarian law."

The High Commissioner said the unhindered presence of international observers, including media, would help calm the situation and curb excesses.

She also voiced serious concern about the treatment of journalists by the Libyan authorities, and called on the Government to immediately release those detained. At least two journalists have been killed, and some 16 others are missing, including ten international journalists and six Libyans. Dozens of others have been detained, assaulted, physically abused – possibly to the point of torture – or expelled.