Locals carry injured Japanese aid worker doctor Tetsu Nakamura to a hospital in Jalalabad eastern Afghanistan, on Dec. 4, 2019. (AP Photo/Wali Sabawoon)

In this image taken from video, locals inspect the site of a gun attack on a Japanese aid worker's truck, on Dec. 4, 2019, Nangarhar province, eastern Afghanistan. (AP Photo)

KABUL, Afghanistan (AP) -- A shooting ambush in eastern Afghanistan on Wednesday killed a Japanese physician and aid worker widely respected and beloved in the war-scarred nation, triggering an outpouring of grief among the people whose lives he helped change for the better.

The leaders of Japan and Afghanistan expressed their condemnations of the attack that took the life of Tetsu Nakamura, and also killed five Afghans, including the doctor's bodyguards, the driver and a passenger, hospital spokesman Gulzada Sanger said.

Nakamura, 73, had worked in the eastern Nangarhar province for over a decade, taking the lead in water projects in rural areas, which earned him the nickname ''Uncle Murad'' for his services to the people. Afghan President Ashraf Ghani awarded him honorary Afghan citizenship in April.

Nakamura died of his wounds shortly after gunmen opened fire on his car on Wednesday morning on a road in Nangarhar. According to the provincial governor's spokesman, Attaullah Khogyani, Nakamura was heading to the provincial capital, Jalalabad, when the attack took place.

He was critically wounded and underwent surgery at a local hospital but died shortly after, while being airlifted to the Bagram airfield hospital in the capital, Kabul, said Sanger.

Japanese Prime Minister Shinzo Abe expressed shock at the brutal killing.

"As a doctor, Mr. Nakamura made great contributions in areas of medical care in Afghanistan," Abe told reporters in Tokyo, stressing that Nakamura risked his life daily "in a dangerous and intense region."

Nakamura had headed the Japanese charity, Peace Medical Service, in Nangarhar since 2008. He came to Afghanistan after a Japanese colleague, Kazuya Ito, was abducted and killed.

Nakamura was credited with changing a vast desert stretch in Nangarhar known as Gamber to lush forests and productive wheat farmlands.

President Ghani's spokesman, Sediq Sediqqi, condemned the killing, calling it a "heinous act and a cowardly attack on one of Afghanistan's greatest friends."

"Dr. Nakamura dedicated all his life to change the lives of Afghans, worked on water management, dams and improvement of traditional agriculture in Afghanistan," Sediqqi added.

Ghani expressed his condolences in a telephone conversation with Japanese Ambassador Mistuji Suzuka in Kabul and instructed authorities to find and punish the perpetrators behind the attack.

The Nangarhar governor, Shah Mahmood Meyakhail, expressed his condolences, saying that the people of the province were all saddened and remain thankful for the services the Japanese physician provided for over a decade.

Hundreds of Afghans posted photographs of Nakamura on their social media pages, condemning the killing and underscoring how respected the Japanese physician was.

In Fukuoka, southwestern Japan, where the charity is based, the organization's spokesman Mitsuji Fukumoto lauded Nakamura's work.

"I still can't believe it. This is unbearable," Fukumoto said of Nakamura. "He had won the people's trust by bringing not weapons but water through irrigation."

No one immediately claimed responsibility for the attack, the second in as many weeks targeting aid workers in Afghanistan.

Nangarhar police said they were searching for the attackers, who fled the scene, and that an investigation was underway.

In late November, an American working for the United Nations mission in Afghanistan was killed and five Afghans, including two staff members of the mission, were wounded when a grenade hit a U.N. vehicle in Kabul.

The Taliban, who along with the Islamic State group, operate across the province, denied involvement in Wednesday's attack.

Taliban spokesman Zabihullah Mujahid tweeted that the insurgent group "has no connection" to Wednesday's shooting and does not consider the Japanese charity a target in the holy war the Taliban are waging to create an Islamic emirate.

The Taliban control or hold sway over nearly half of Afghanistan, staging near-daily attacks that target Afghan forces and government officials but also kill scores of civilians.

Before coming to Afghanistan, Nakamura worked in Pakistan where he treated Afghan refugees and also those with leprosy. But Afghanistan captured his heart.

"Whenever you go to a farm or small town, there is always life there unchanged from the past," he wrote. "Our efforts co-exist with the tears and laughter of the people there."

"I hope with the bottom of my heart that we can become those who can gather the conscience of all people, overcoming differences of views, and become a glacier, setting our eyes on those streams that noisily appear and then disappear on the surface of our planet, overcoming challenges with conviction to build something that is enduring," Nakamura said.