Mr Mastrogiacomo, 52, survived a harrowing two weeks of captivity during which he was marched between desert hideouts and forced to watch the execution of his driver.
“This is the most wonderful moment of my life,” the Italian said after reaching safety at an Italian-run hospital in Lashkar Gah, the capital of Helmand province, on Monday.
But yesterday uncomfortable questions loomed about the price paid for Mastrogiacomo’s liberation.
Gina Strada head of the Italian non-governmental organisation Emergency, which runs a hospital in Lashkar Gah, told La Stampa that President Karzai had authorised the release despite protests in his own government.
“The Afghan government was not a big help,” she said. “[The Italian ambassador] spent hours and hours fighting with ministers and Afghan officials who refused to carry out Karzai’s orders.”
Karim Rahimi, an Afghan government spokesman, admitted “some demands” had been met but refused to specify how many prisoners had been freed. “This was an exceptional case and it will never happen again,” he said.
Mr Karzai authorised the deal to preserve the “friendship” of Italy, which has 1,800 soldiers in Afghanistan, he said. Other government officials confirmed privately that up to five militants had been freed.
Mastrogiacomo, his driver and translator were kidnapped in Naw Zad, a rebel-dominated district near Lashkar Gah, on March 5. The reporter, who had arrived in the province just days earlier, was apparently seeking an interview with the Taliban.
In an account of his abduction published yesterday he said they were bound hand and foot and shuttled between 15 different locations “as small as sheep pens, in the middle of the desert”.
The prisoner exchange deal came too late for the Afghan driver, Syed Agha, who was beheaded in the desert after a Taliban court found him guilty of espionage.
“I can still see it now,” wrote Mastrogiacomo. “I get off my knees. Four men grab the driver and shove his face into the sand. They cut his throat and continue until they have cut off his whole head.
“He is not able to make a gasp. They clean the knife on his tunic. They tie his severed head to his body. They bring it to the river and let it go.”
News of the killing triggered an impassioned response in Lashkar Gah, where 150 people protested outside the Italian-run hospital and accused the Afghan and Italian governments of double standards.
“[Karzai] was talking about the Italian but said nothing about his Afghan driver,” said relative Khan Jan. “Now we know he is dead and we don’t even get the body.”
At one point security forces arrested the Afghan hospital head, Rahmatullah Hanafi, in an apparent attempt to appease the demonstrators, who had threatened to prevent Mastrogiacomo from reaching Lashkar Gah airstrip.
Last night there was no word on his translator, Ajmal Naskhbandi. The Italian ambassador, Ettore Francesco Sequi, said he hoped he would be released soon.
While La Repubblica celebrated the release of its correspondent, other Italian newspapers were more equivocal. “The government sold out,” ran the headline in the rightwing Libero newspaper, over an editorial that called the swap “straight-out repugnant”.
La Stampa said: “If this is the just price chosen to pay to save the life of Mastrogiacomo, it’s up to [the government] to show Italy is still able to continue fulfilling its role in Afghanistan without becoming the weak link in the international alliance.”
Opposition politicians called on the prime minister, Romano Prodi, to explain himself in parliament.
Rome has been accused of bowing to kidnappers several times before. In Iraq several Italian hostages were released amid rumours of large payments.
In 2004 the Italian Red Cross said it treated four Iraqi “terrorists” and their children to help free two charity workers.
The Committee to Protect Journalists said southern Afghanistan was increasingly becoming an “Iraq-like” place where western media rely on local reporters. “In many ways it’s outsourcing the risk,” said Bob Dietz.
Across the border in Pakistan’s tribal areas more than 46 people died in a gun battle between local and foreign militants in the South Waziristan tribal area. At least two children were killed and 20 injured when a stray mortar from the fighting hit their school bus.
It was the second such battle in recent weeks, indicating that the Pakistani government is encouraging local tribesmen to rise against al-Qaida linked militants who have settled in the areas in recent years.