Olympic competition kicked off Wednesday with women's football (soccer) matches, although opening ceremonies in London are two days away.
The United States began defending its 2008 Olympic gold medal by beating France 4-2 in Glasgow, Scotland. Alex Morgan scored twice for the U.S., which recovered from a two-goal deficit.
Britain beat New Zealand 1-0 in the Welsh capital, Cardiff.
The action started as a strike that threatened to cause disruption at London's Heathrow Airport was called off by Britain's Home Office, the leading U.K. department in charge of immigration.
A union representing immigration staff at the airport reached a deal with the government and canceled plans for a walkout.
The strike could have created serious delays for travelers arriving for Friday's opening ceremony in London.
Meanwhile, the International Association of Athletics' Federations suspended nine track and field athletes for doping violations, in a crackdown on the use of prohibited substances leading up to the Olympics.
More than 10,000 athletes are competing in 26 sports at the Olympics. The competition runs until August 12.
Some information for this report was provided by AP and AFP.