UN climate negotiators agreed to an investigation after protesters smashed a sign emblazoned "Saudi Arabia" and dropped it in toilet after Riyadh blocked a study of deeper cuts in greenhouse gases.

Many countries condemned the protest, after Saudi Arabia blocked a request by small island states at the May 31-June 11 talks for a study of tougher cuts in greenhouse gases to help slow a rise in world sea levels.

Mexico's delegate Luis Alfonso de Alba, whose country will host the main climate talks in late 2010, said he was initiating an investigation by the UN Climate Change Secretariat.

Pieces of the smashed Saudi Arabia sign -- about 30 cm and placed on a table to identify the delegation during negotiations -- were dropped in a toilet and then photographed, delegates said. The pictures were then put up on some walls.

"This is a serious incident. We should fully support that the secretariat should carry out an investigation and the result should be informed to the parties," Chinese delegate Su Wei said.

Lebanon's delegate also said that the Saudi flag was abused during a protest in the conference hall after Saudi Arabia blocked the small island state's push.

Saudi Arabia has often expressed worries at UN climate negotiations that a shift towards renewable energies will undermine its oil export earnings.

It opposed the small island state's push for a study of limiting global warming, saying that wider issues such as the impact on exporters, also had to be taken into account. – Reuters