Pro-Muammar Gaddafi fighters shelled the rebel-controlled town of Misrata, killing at least 10 people on Friday.
Gaddafi’s men started attacking the western town once again on Thursday. It was the scene of a two-month siege earlier in the Libyan conflict.
Russia, which abstained on the UN resolution authorising the NATO-led intervention, says it wants to broker a peace deal.
Moscow’s African envoy Mikhail Margelov has already met with rebel leaders and said he will soon hold talks with Gaddafi aides.
Russia has now joined the West in telling the Libyan leader to step down but says NATO’s airstrikes go beyond its original remit of protecting civilians.
NATO allies came in more criticism on Friday.
Outgoing US Defence Secretary Robert Gates said fellow members rely too heavily on Washington to make up the shortfall left by cuts to the others’ defence budgets.
The US spends 480 billion euros a year on defence, nearly 75 percent of the total defence spending by all NATO members.
The combined military spending of all 26 European members is less than 150 billion euros.