A long-running dispute between Malaysia and Singapore over land reclamation is to be settled by independent arbitrators, a United Nations tribunal has ruled.
But Malaysian Prime Minister Mahathir Mohamad said Singapore should not be allowed to continue the work while the arbitration process was under way.
"If they continue their work, it would be too late," said Mr Mahathir.
"By the time we have a final decision, the reclamation might have just done permanent damage," he said.
Malaysia insists that the Singaporean reclamation work in the Straits of Johor, which separates the two countries, will damage the area's marine environment.
After two months of unsuccessful bilateral talks, Malaysia brought the case to the International Tribunal of the Sea, based in Germany, saying that negotiations without outside help had proved futile.
Judge Dollier Nelson said the two nations should establish a group of independent experts to monitor the project.
He did not grant Malaysia's request to halt the work for the duration of the proceedings, but ordered Singapore "not to conduct its land reclamation in ways that might cause irreparable prejudice to the rights of Malaysia".
Both countries claimed the ruling was a victory for their side of the argument.
Malaysian Foreign Minister Syed Hamid Albar told the Associated Press on Thursday: "Now Singapore cannot brush us aside
and say that Malaysia has no case."
Singapore's foreign ministry also welcomed the ruling, saying: "The decision supports Singapore's position that there was no
need for Singapore to stop its reclamation works."
"It upholds the position which Singapore has maintained all
along... that Singapore's reclamation works, which are carried out
strictly within its territorial waters, are in full compliance with
Singapore insists it needs to go ahead with the reclamation to accommodate its growing population.
Since separating from Malaysia in 1965, Singapore has
reclaimed more than 100 square kilometres (40 square miles)