Mexico City - Mexico City on Monday decided to limit business activity to stop the spread of swine flu, which has so far killed about 103 people in the country, Mayor Marcelo Ebrard said. "We need everyone to take the necessary measures. We have to keep up the effort this week - we are in a critical week," Ebrard said.

The mayor did not give specific details of the new measures to be taken, but the Business Coordinating Council has told its members to stagger working hours as that would prevent concentrations of people in one area.

On Monday there was significantly less activity than usual in Mexico City, a bustling city of 22 million people, largely because schools and universities have suspended until at least May 6.

The High Court of Justice and the Local Arbitration Board also closed their offices for the week.

Health officials said they did not still know how many of the 103 people who have died of influenza in recent weeks suffered from the new swine flu virus that has prompted a global alert. But at least 20 cases were confirmed as swine flu.

Mexico City authorities were also planning to increase the distribution of face masks throughout the public transport system, although there was no decision yet to shut down subways or buses.

Mexican states less affected by the epidemic, such as Nuevo Leon, Coahuila, Chiapas and Zacatecas, also decided to shut down schools on Monday and Tuesday. (dpa)