BBC News with Nick Kelly

The leaders of the world's eight most powerful nations have sharply criticized North Korea and Iran. They condemned North Korea for the sinking of a South Korean warship in March and called on the Iranian leadership to respect human rights and the rule of law. Andrew Walker reports.

In a strongly worded section in the summit communique, the G8 said they deplored the sinking of the South Korean vessel with the loss of 46 lives. They called on North Korea to refrain from committing any attacks or threatening hostilities against its neighbour. The G8 also expressed concern that nuclear and missile tests by the North have increased tension, and called on the country to abandon all nuclear weapons. In the Middle East, the communique described the Israeli blockade of Gaza as "unsustainable" and called for humanitarian and commercial goods to be allowed in and out of the territory.

The G8 leaders will be joined by their counterparts from emerging countries later on Saturday for a meeting of the G20 grouping.

Groups of anti-globalization protesters have clashed with police in Toronto near the venue of the G20 meeting. A police car was set ablaze. A television reporter said the demonstrators were hurling objects at the police. It's thought the violence involves people who broke away from a peaceful march in the city.

President of Afghanistan Hamid Karzai says neighbouring states must do more to stop illegal drugs, such as opium being smuggled out of his country. Mr Karzai said Afghanistan on its own didn't have the resources to stop the drugs trade, and he said forces outside Afghanistan were fuelling the growth of opium poppies.