Leaders of the Group of Eight (G8) Thursday kicked off their annual summit in the Scottish resort of Gleneagles, while London's subway and bus service was suspended due to a series of blasts that hit the British capital.

Explosions devastated London's transport system during rush hour Thursday morning, causing a number of casualties.

Home Secretary Charles Clarke was cited by local media as saying that the blasts caused "terrible injuries," and police said there were at least 90 casualties.

Meanwhile, the leaders of the most industrialized countries started conversation on climate change and poverty eradication in Africa in their annual summit.

Global warming has been grabbing headlines in the past several weeks while US President George W. Bush continued his refusal to recognize the scientific evidence of greenhouse gas emission and climate change.

As he traveled to Scotland for the summit on Wednesday, Bush openly acknowledged for the first time the role of human activity in causing global warming.

"I recognize the surface of the earth is warmer and that an increase in greenhouse gases caused by humans is contributing to the problem," he said during a visit to Denmark en route to Gleneagles.

Meanwhile, Blair called on other seven countries of the group to work in partnership with the major emerging economies, to cooperate on the research and technology of clean and renewable energy.

The leaders are expected to focus on aid and poverty reduction efforts in Africa during Friday's discussions, which will be joined by leaders of Algeria, Ethiopia, Ghana, Nigeria, Senegal, South Africa and Tanzania.

Britain has called on the G8 countries to double their aid to Africa by an extra 25 billion US dollars per year by 2010, then an additional 25 billion US dollars per year by 2015.

The European Union has committed to double its aid to Africa from 40 billion US dollars last year to 80 billion US dollars by 2010. Washington also offered to add an extra 4.5 billion US dollars while offers from Canada and Japan appear to take the total to 47 billion US dollars.

Last month in London, financial ministers of the G8 countries agreed on plans that match 100 percent bilateral debt write-off with 100 percent multilateral debt cancellation for 38 African countries.

Secretary-General of the United Nations Kofi Anna, President of the European Commission Jose Manuel Barroso and the head of World Bank Paul Wolfowitz were also invited to join the summit meeting.

Security is extremely tight in and around Gleneagles Hotel compound, with more than 10,000 British policemen on guard.

Thousands of protesters are demonstrating on the edge of the compound of Gleneagles Hotel on Thursday. More protests are reported to be taking place during the meeting.

The G8 consists of Britain, Canada, France, Germany, Italy, Japan, the United States and Russia.

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Source: Xinhua