"The secretary general has consistently called for restraint and caution to avoid civilian casualties. He of course recognizes and appreciates NATO's efforts to avoid civilian casualties," a UN spokesman, Farhan Haq, told reporters.

Ban sounded the alarm over civilian deaths and called for new efforts to find a political solution between Libya's long time strongman Moamer Qadhafi and opposition rebels in a statement released by his office on Thursday.

Without specifically naming any side, Ban called through a spokesman on "all parties" to use "extreme caution" in the battle.

"The secretary general is deeply concerned by reports of the unacceptably large number of civilian casualties as a result of the conflict in Libya," said a statement.

Ban "calls on all parties to exercise extreme caution in their actions, in order to minimize any further loss of civilian life," it added.

The UN chief has been a staunch defender of the NATO air campaign against Qadhafi, which began in March.

The air attacks have drawn criticism from some members of the UN Security Council, including Russia, China, Brazil, India and South Africa, who say the action goes beyond UN resolutions on Libya.

NATO has insisted that its attacks are in keeping with UN resolutions passed this year which allow military action to protect civilians in Libya.

Copyright AFP (Agence France-Presse), 2011