Rusutsu, Japan (AP): U.S. President George W. Bush put advancing world trade talks and increasing aid to Africa high on his agenda Sunday for an upcoming summit of major economic powers that is also expected to focus on energy and climate change.

Bush met Sunday with Japanese Prime Minister Yasuo Fukuda, the first of many expected meetings between world leaders on the sidelines of the Group of Eight summit that begins Monday on Japan's northern island of Hokkaido.

The three-day summit also includes meetings between the G-8 leaders and heads of several African countries and major developing nations including China, Brazil and India _ a total of 22 leaders.

Host Japan has made climate change a key topic at the meeting, and many hope the G-8 will give some indication of its commitment to cutting greenhouse gases to move forward U.N.-led talks aimed at replacing the Kyoto Protocol on climate change, which expires in 2012. Negotiators face a deadline of December 2009, when some 190 nations will meet in Denmark.

Fukuda would like to emerge from the summit with an agreement on a 50 percent overall reduction in greenhouse gases, blamed for global warming, by 2050. Some European countries and developing nations also want to set targets for cutting emissions by 2020. Scientists say those targets are needed to avoid the worst effects of global warming.

But Bush reiterated his position that rapidly developing nations such as China and India also need to commit to emission-reduction standards. He said he was ``realistic enough to tell you that if China and India don't share that same aspiration, that we're not going to solve the problem.''

Bush also emphasized the urgency of providing aid for Africa. He called on wealthy nations to provide mosquito nets and other aid to prevent children from ``needlessly dying from mosquito bites.''

``I'm concerned about people going hungry. We'll be very constructive in the dialogue about the environment _ I care about the environment _ but today there's too much suffering in the continent of Africa,'' he said. ``Now is the time for the comfortable nations to step up and do something about it.''

In addition to food and energy, Bush said he hopes to spend time talking with other leaders about moving forward on the World Trade Organization talks, which have become stuck as rich and poor nations bicker over changes to their subsidies and trade taxes.

``This is an opportunity for us, Mr. Prime Minister, for us to promote free and fair trade,'' said during a news conference with Fukuda. ``The best way to help impoverished around the world is through trade.''

The site of this year's meetings is a heavily guarded luxury resort on a hilltop overlooking picturesque Lake Toya, formed in a crater left behind by a collapsed volcano.

Hundreds of protesters held a second day of demonstrations against the G-8 in Sapporo, a city about 65 miles (100 kilometers) northeast of Lake Toya. They demanded the G-8 be dissolved and urgent measures be taken to solve climate change and world hunger.

``Down with imperialism,'' said one large red banner carried at the front of the march.

Security kicked into high gear over the weekend, with riot police in body armor monitoring checkpoints along roads leading to the summit site through the rolling farmland.

Japan has mobilized roughly 20,000 police officers in Hokkaido, many of them brought in from other parts of the country, to avert any terrorist attacks. The Yomiuri newspaper reported that F-15 fighter jets would patrol during the summit.

German Chancellor Angela Merkel said the G-8 leaders will discuss how they can toughen sanctions on Zimbabwe in the wake of President Robert Mugabe's widely denounced presidential election runoff victory.

``We will confer on how we can toughen sanctions against Zimbabwe, and I hope that we will also get support from our African colleagues here,'' Merkel said in her weekly video message.

South African President Thabo Mbeki, whom Zimbabwe's opposition has accused of favoring Mugabe, and Nigerian President Umaru Yar'Adua have been invited to meet with the G-8 leaders on Monday.

The EU already has travel bans and an asset freeze in place on Mugabe and other senior Zimbabwean officials. The U.S. also is seeking international sanctions against Mugabe and his top aides.

With global oil prices surging, the G-8 leaders are expected to urge major oil producers to increase supplies while also calling for steps to improve energy efficiency and develop alternative sources of energy within their own economies. Oil spiked to a record US$145.85 a barrel on Thursday.

However, observers have questioned the effectiveness of any calls by the G-8 to boost oil production when the group does not include Saudi Arabia, the world's largest exporter of crude, or any OPEC members.

Likewise, there is growing criticism that the G-8 excludes other major economies such as China, India, Brazil, Mexico and South Africa. Leaders of those nations are to meet with the G-8 leaders on Wednesday.