"As a person and as prime minister, I feel sympathy from the bottom of my heart to former comfort women, who experienced hardships," Abe told members of the US congress on Thursday.
 
"I feel deeply sorry that they were forced to be placed in such extremely painful situations," he added.
 
On Friday Abe is due to begin formal summit talks with George Bush, the US president, at the president's Camp David retreat.
 
Former comfort women says Japan
must do more to apologise [EPA]
Topping the agenda are security issues involving North Korea, Iraq and Afghanistan, while Abe is expected to reafirm Japan's support for Washington as one of its closest allies.
 
"It is vitally important for both Japan and the United States to [maintain] peace and stability of the Asian region, where unstable elements such as the Korean peninsula still exist," he said.
 
"It is necessary to further strengthen the Japan-US alliance. I would like to work together with the United States to continue dealing with various issues such as North Korea, Iraq and Afghanistan."
 
In his meetings on Thursday members of congress praised Japan's contribution to Iraq's reconstruction and called for closer cooperation to jointly tackle global issues, according to a Japanese official.
 
Abduction issue
 

"I will express my stance with an iron will of seeking a solution to the abduction issue"

Shinzo Abe,
Japanese PM

Abe is also expected to seek Bush's reassurances on on the issue of Japanese citizens abducted by North Korean agents in the 1970s and 80s
 
"I will express my stance with an iron will of seeking a solution to the abduction issue," said Abe, who rejected a US-backed aid-for-disarmament deal with North Korea due to the kidnapping dispute.
 
Advisors have said Bush will reassure the Japanese leaders that the US will not remove North Korea from its list of terrorism sponsors until the abductee issue is resolved.