World leaders – including U.S. President Barack Obama – have arrived in Toronto for the G8 and G20 summits, which will focus on repairing the global economy as the world emerges from the worst financial crisis since the Great Depression.

In Huntsville, Ontario, Canadian Prime Minister Stephen Harper greeted President Obama, Russian President Dmitry Medvedev, British Prime Minister David Cameron and French President Nicolas Sarkozy as they arrived in this town – just north of Toronto – as the G8 summit got underway.

The G8 members are confronting an estimated $18 billion shortfall on a 2005 pledge to raise their combined aid to the poorest countries by at least $50 billion.

The G8 summit concludes Saturday – which will be followed by the G20 meeting in downtown Toronto.