Iraq forces free German woman kidnapped in Baghdad
Iraq's interior ministry said a joint task force, including the elite Falcons intelligence forces and federal police and anti-crime units, carried out the operation in east Baghdad.
Interior Minister Othman al-Ghanemi handed Mewis over to the German embassy in Baghdad, the ministry said.
Mewis has worked in Baghdad since 2013 and was one of the few foreigners who lived outside the high-security Green Zone, where most diplomatic missions are located.
She ran arts programmes at Iraqi collective Beit Tarkib and was close to many young photographers and painters.
Mewis was leaving her office in central Baghdad on Monday evening when unidentified assailants in two cars, including a white pickup truck typically used by Iraqi security forces, abducted her.
Police officers at the local station witnessed the abduction but did not intervene, the source added.
German Foreign Minister Heiko Maas said he was "relieved" that Mewis was freed, confirmed she was at the embassy in Baghdad and thanked the Iraqi government for its efforts.
Diplomatic sources told AFP she was in good health.
The details of her release and the identity of her kidnappers remain hazy, with the interior ministry and Supreme Judicial Council saying they were still trying to find the perpetrators.
A security source told AFP Mewis was freed from a location in east Baghdad as part of an exchange.
"Hours after she was kidnapped, security forces detained a man involved in the operation, who claimed he belonged to a faction close to the Hashed al-Shaabi," the source said.
"They agreed to release him in exchange for her," the source added.
Hardliners within the Hashed, a state-sponsored network of armed groups including many backed by neighbouring Iran, have been accused of kidnapping or intimidating Iraqi activists in the past.
Swathes of east Baghdad, including the densely populated Sadr City district, are inaccessible to state security forces.
The Hashed made no formal statement on Mewis's kidnapping, but on Friday a spokesman said he hoped Iraqi authorities would look into how she had been "secretly" present in Baghdad without security authorisation.
Moqtada Sadr, a populist and divisive Shiite cleric, hailed Mewis's release and called her a "guest."
'Nervous' after assassination
Mewis's phone was still unreachable on Friday and her friends had not heard from her.
A friend of Mewis told AFP she had been worried following the killing of Hisham al-Hashemi, an Iraqi scholar who had been supportive of anti-government protests last year.
"I spoke to her (Mewis) last week and she was really involved in the protests too, so she was nervous after the assassination," said the friend, Dhikra Sarsam.
Large demonstrations erupted in Baghdad and Iraq's Shiite-majority south last year, railing against a government seen as corrupt, inept and beholden to Iran.
Around 550 people died in protest-related violence, including two dozen activists who were shot dead by unidentified men, usually on motorcycles.
Dozens more were kidnapped, some of whom were later released near their homes. The whereabouts of others remain unknown.
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Amnesty International has slammed the incidents as "a growing lethal campaign of harassment, intimidation, abductions and deliberate killings of activists and protesters".
This year has seen a worrying spike in abductions of foreigners, who had not been targeted in several years.
On New Year's Eve, two French freelance journalists were taken hostage for 36 hours and three French NGO workers were held for two months.
In both cases, neither the kidnappers nor the conditions of the hostages' release were revealed.