US President Barack Obama's speedy visit to Afghanistan is aimed at winning the domestic election and shows confidence in Kabul's government, experts said on Wednesday.

"Obama's visit serves his re-election," said Jin Canrong, an expert on American studies at Renmin University of China. "He is attempting to show the capacity and strength of his government and win the trust of voters.

"Security is a big problem for Afghanistan after NATO's military withdrawal, Obama needs to encourage the Afghanistan government."

To mark the anniversary of Osama bin Laden's death, Obama paid his third visit to Afghanstan on Wednesday, signing a strategic pact with Kabul and delivering an election-year message to Americans that the war is winding down, Reuters said.

During his trip, Obama and Afghan President Hamid Karzai signed a strategic partnership agreement that sets out a long-term US role in Afghanistan. The deal may provide Afghans with reassurances that they will not be abandoned when most NATO combat troops will leave as planned in 2024, according to Reuters.

Republican candidate Mitt Romney, Obama's election rival, said he was "pleased" by Obama's visit to Afghanistan.

"I am pleased that President Obama has returned to Afghanistan. Our troops and the American people deserve to hear from our president about what is at stake in this war ... Success in Afghanistan is vital to our nation's security," Romney said on his website.

Obama has three target groups: the Afghan people, the international community and domestic voters, said Tao Wenzhao, an expert at the Institute of American Studies of the Chinese Academy of Social Sciences.

Obama would like to pacify the Afghanistan people, show Washington's responsibility to the international community, and show his government's capacity and strength to US citizens, Tao said.

Tao added that the US president is responding to suspicions that the US and Afghanistan are suffering from bad ties because of recent incidents, including the burning of a Quran at the US-run Bagram Air Base near Kabul, and the killing of 16 Afghan villagers by a US soldier.

Despite domestic political considerations, no one could deny that the demise of bin Laden is a victory for the present US government, Tao said.

The strategic partnership agreement guarantees America's continued economic and development aid as well as the promise of a future security arrangement, the New York Times reported.

Two other deals recently signed by the countries gave the Afghan government authority over detentions and transferred primary authority over special operations raids, including night raids, the paper said.

"This agreement will close the season of the past 10 years and is going to open an equal relationship season. With the signing of this agreement, we are starting a phase between two sovereign and independent countries that will be based on mutual respect, mutual commitments and mutual friendship," Karzai said.

"There will be an essential change for the post-war US-Afghan ties, because Afghanistan is not a sovereign country before the withdrawal of US military," Tao said. "The agreement marks the beginning of the new bilateral relationship after the war."

US President Barack Obama's speedy visit to Afghanistan is aimed at winning the domestic election and shows confidence in Kabul's government, experts said on Wednesday.

"Obama's visit serves his re-election," said Jin Canrong, an expert on American studies at Renmin University of China. "He is attempting to show the capacity and strength of his government and win the trust of voters.

"Security is a big problem for Afghanistan after NATO's military withdrawal, Obama needs to encourage the Afghanistan government."

To mark the anniversary of Osama bin Laden's death, Obama paid his third visit to Afghanstan on Wednesday, signing a strategic pact with Kabul and delivering an election-year message to Americans that the war is winding down, Reuters said.

During his trip, Obama and Afghan President Hamid Karzai signed a strategic partnership agreement that sets out a long-term US role in Afghanistan. The deal may provide Afghans with reassurances that they will not be abandoned when most NATO combat troops will leave as planned in 2024, according to Reuters.

Republican candidate Mitt Romney, Obama's election rival, said he was "pleased" by Obama's visit to Afghanistan.

"I am pleased that President Obama has returned to Afghanistan. Our troops and the American people deserve to hear from our president about what is at stake in this war ... Success in Afghanistan is vital to our nation's security," Romney said on his website.

Obama has three target groups: the Afghan people, the international community and domestic voters, said Tao Wenzhao, an expert at the Institute of American Studies of the Chinese Academy of Social Sciences.

Obama would like to pacify the Afghanistan people, show Washington's responsibility to the international community, and show his government's capacity and strength to US citizens, Tao said.

Tao added that the US president is responding to suspicions that the US and Afghanistan are suffering from bad ties because of recent incidents, including the burning of a Quran at the US-run Bagram Air Base near Kabul, and the killing of 16 Afghan villagers by a US soldier.

Despite domestic political considerations, no one could deny that the demise of bin Laden is a victory for the present US government, Tao said.

The strategic partnership agreement guarantees America's continued economic and development aid as well as the promise of a future security arrangement, the New York Times reported.

Two other deals recently signed by the countries gave the Afghan government authority over detentions and transferred primary authority over special operations raids, including night raids, the paper said.

"This agreement will close the season of the past 10 years and is going to open an equal relationship season. With the signing of this agreement, we are starting a phase between two sovereign and independent countries that will be based on mutual respect, mutual commitments and mutual friendship," Karzai said.

"There will be an essential change for the post-war US-Afghan ties, because Afghanistan is not a sovereign country before the withdrawal of US military," Tao said. "The agreement marks the beginning of the new bilateral relationship after the war."