Nepal must take lessons from earthquake-hit countries such as Mexico and strictly enforce existing building laws as it prepares to rebuild from two major quakes, a senior United Nations official said Wednesday.

Earthquakes on April 25 and May 12 killed at least 8,622 people and damaged 756,000 houses and other buildings in Nepal.

U.N. Assistant Secretary-General Magdy Martinez-Soliman said good urban planning is vital in disaster-prone areas—something that Mexico learned after being hit with a 1985 quake that killed at least 9,500 people and flattened parts of Mexico City.

“If you are in a disaster-prone area, you absolutely need to know that good urban planning is fundamental,” said Martinez-Soliman. “That is what the Mexicans learned once they were hit in 1985—they never [made] the mistakes again. They planned in an orderly fashion, their building codes were absolutely stringent and the building codes were enforced.”

Since the recent earthquakes, Nepalese authorities have been criticized for not enforcing building laws and allowing tall and weak buildings to be built. Thousands of buildings in Kathmandu were damaged in the quakes, and many have been declared unsafe and need to be demolished.

Nepal’s government this week banned construction of new buildings for two months and said it would review existing building laws. No new building permits will be issued, and houses that are already in the process of being built can only be up to two stories high.

Martinez-Soliman said the problem in Nepal is not legislation but rather enforcement and implementation of the laws.

“You need strong political will,” he said. “You need to reprimand those who cut corners. You need to rein in those who try to make additional profit by disrespecting the law. The challenge is implementation. Definitely, it is about capacity and political will behind implementing the laws.”

Nepal has announced a $2 billion earthquake reconstruction and rehabilitation fund, with the government contributing $200 million and seeking the remainder from donor agencies and nations. The government plans to hold an international conference next month to seek financial support.

The U.N. has made an international appeal for $423 million for its agencies working in Nepal, but a slow response is worrying because the rainy season is about to begin and many people are still without permanent shelter.