The mother of Kenneth Bae, a US citizen jailed in North Korea, said Tuesday she was "more anxious than ever" to secure her son's release after visiting him in prison.
Myunghee Bae said she had been able to see her son three times during her five-day stay in North Korea and was "relieved" to see that his health had improved in the past two months.
Bae was earlier reported to be suffering serious health problems and to have lost more than 50 pounds (23 kilogrammes) since being jailed nearly a year ago.
Despite the improvement, Bae's mother said she was increasingly desperate for her son to return home.
"I was happy to see him and to hold him, but it broke my heart to leave him behind. I am more anxious than ever to bring him home," she said in a written statement released by the family.
"His year-long imprisonment has taken a heavy toll not only on Kenneth but on the whole family; every day the pain and anxiety continue to carve a deep scar on all of our hearts," she added.
Bae, a 45-year-old tour operator also known by his Korean name Pae Jun-Ho, was arrested in November as he entered the northeastern port city of Rason.
He was sentenced to 15 years' hard labour on charges of seeking to topple the government.
The court described Bae as a militant Christian evangelist who smuggled inflammatory material into the country and sought to establish a subversive base in Rason.
Bae was sentenced amid heightened military tensions on the Korean peninsula, leading to suggestions Pyongyang hoped to use him as a diplomatic bargaining chip to extract concessions from Washington.
The North has staunchly denied the charge, and indicated that it wants policy changes, not diplomacy, from Washington to secure Bae's freedom.
In August, North Korea issued and then rescinded an invitation for Robert King, the US special envoy for North Korean human rights issues, to visit Pyongyang for talks on Bae's release.
North Korea has in the past freed detained Americans after visits from high-level emissaries.
In 2011, a US delegation led by King secured the release of Eddie Jun Yong-Su, a California-based businessman, detained for apparent missionary activities.
In 2010 former US president Jimmy Carter won plaudits when he negotiated the release of American national Aijalon Mahli Gomes, sentenced to eight years of hard labour for illegally crossing into the North from China.
On another mercy mission a year earlier in 2009, former president Bill Clinton won the release of US television journalists Laura Ling and Euna Lee, jailed after wandering across the North Korean border with China.
In her statement, Bae's mother pleaded with the US government to do "everything in their power to secure my son's release soon."
She also said she was "very grateful" to the authorities in Pyongyang for allowing the prison visits.
The US State Department stressed that her trip had not been arranged by Washington, although it had helped in coordinating the trip with the Swedish Embassy in Pyongyang which looks after US interests there.