MOSCOW, June 29 (RIA Novosti) - The World Health Organization (WHO) on Monday confirmed 70,893 officially registered A/H1N1 cases and 311 deaths in 116 countries and territories worldwide.

The number of infected grew by 11,079 people over the weekend, while the death toll increased by 48 people.

The United States has seen the most fatalities with 27,717 cases and 127 deaths. Mexico has become the second most affected country, with 8,279 cases and 116 deaths. Other countries to be hit include Canada (7,775 cases, 21 deaths), Chile (5,186 cases and seven deaths), Britain (4,250 cases, one death) and Australia (4,038 cases, seven deaths).

WHO decided to raise its pandemic alert level to the maximum of 6 on June 11.

An influenza pandemic is an epidemic of an influenza virus that spreads on a worldwide scale and infects a large proportion of the human population.

There were three flu pandemics in the last century. The 1918 Spanish flu was the most serious, claiming over 50 million lives. It was followed by the Asian Flu in 1957 with up to 4 million deaths, and the Hong Kong Flu in 1968 resulting in about 1 million deaths.