The Ontario government is confirming four cases of swine flu in Ontario -- and all are in the GTA. Three have been confirmed in Durham Region and one in York Region.

Officials say all four cases are considered mild and the patients are recovering at home.

The province says it will step up communication to the public to help people take precautions.

The announcement of the four Toronto-area cases came just hours after city officials said they were prepared to battle any potential swine flu infections in the city.

Mayor David Miller says the city has learned from the 2003 SARS outbreak, which killed 44 people.

Dr. David McKeown, Toronto's Medical Officer of Health, outlined Toronto's plan at a news conference on Tuesday.

He said the city will investigate travellers who show flu-like symptoms -- a practice that has been in place for the four years since the SARS crisis.

He also confirmed Toronto has tested its pandemic response programs and increased alerts at emergency rooms. Miller says Toronto Public Health is working with hospitals to monitor any possible patients.

The city is asking that anyone who has recently travelled through Mexico City to see their doctor or call Telehealth Ontario.

"If you're sick, stay home and get well and don't transmit the germs to other Torontonians," says Miller.

Symptoms include cough, fever, headaches, muscle aches and loss of appetite.

City officials remind everyone to practice good hygiene to help contain the spread, including frequent handwashing and sneezing into your sleeve to avoid spreading germs on hands.