Hundreds of demonstrators gathered in freezing temperatures in Brussels on Sunday to urge Belgium to intensify efforts to secure the release of aid worker Olivier Vandecasteele, who is in jail in Iran.
Condemning the case as "hostage diplomacy", the crowd chanted "Free Olivier" and sang Happy Birthday to mark Mr Vandecasteele's 42nd birthday this week.
"The aim is to show the government that we cannot leave an innocent person there," his sister Nathalie told AFP.
Olivier Van Steirtegem, a spokesman for the family, insisted that "every minute, every second counts" and that they hoped growing public pressure for his release would push the Belgian authorities to find a solution more quickly.
Iran arrested Mr Vandecasteele in February 2022, and he has since been held in conditions that Belgium's government has described as "inhumane".
The authorities sentenced him this month to more than 12 years behind bars for "espionage", and to 74 lashes.
His backers and rights groups say he is being held as part of Iran's "hostage diplomacy" to get Belgium to release an Iranian diplomat jfor terrorism.
Assadollah Assadi was found in guilty in 2021 of a plot to blow up an event organised by an Iranian exiled opposition group outside Paris in 2018.

The plot was foiled by European intelligence services, and Assadi, a diplomat stationed in Austria who was identified as having provided the explosives for the bomb, was sentenced to 20 years in prison.
In July last year, Belgium and Iran signed a prisoner-swap treaty that Brussels considered to be way to free Mr Vandecasteele.
But Belgium's Constitutional Court suspended the treaty after exiled Iranian opposition members challenged it on the grounds that it would lead to the release of Assadi.
The court said the suspension was in place pending a ruling on the legality of the treaty.
The Belgian government insists it is doing "all it can" to have Mr Vandecasteele released and says it has strengthened its legal team to plead the case.
More on women's right
UK-EU trade at a glance
EU fishing vessels guaranteed access to UK waters for 12 years
Co-operation on security initiatives and procurement of defence products
Youth experience scheme to work, study or volunteer in UK and EU countries
Smoother border management with use of e-gates
Cutting red tape on import and export of food
The candidates
Dr Ayham Ammora, scientist and business executive
Ali Azeem, business leader
Tony Booth, professor of education
Lord Browne, former BP chief executive
Dr Mohamed El-Erian, economist
Professor Wyn Evans, astrophysicist
Dr Mark Mann, scientist
Gina MIller, anti-Brexit campaigner
Lord Smith, former Cabinet minister
Sandi Toksvig, broadcaster
Killing of Qassem Suleimani
National Editorial: Suleimani has been killed, now we must de-escalate
Mina Al Oraibi: Air strike casts a long shadow over the decade ahead
Matthew Levitt: Iran retains its ability to launch terror attacks
Damien McElroy: A CEO tasked with spreading Iran's influence
Hussein Ibish: Trump's order on solid constitutional ground
Simon Waldman: Cautious Israel keeping a low profile
COMPANY%20PROFILE%20
COMPANY%20PROFILE
On Women's Day
Shelina Janmohamed: Why shouldn't a spouse be compensated fairly for housework?
Samar Elmnhrawy: How companies in the Middle East can catch up on gender equality
The National Editorial: Is there much to celebrate on International Women's Day 2021?
Justin Thomas: Challenge the notion that 'men are from Mars, women are from Venus'
Infiniti QX80 specs
Engine: twin-turbocharged 3.5-liter V6
Power: 450hp
Torque: 700Nm
Price: From Dh450,000, Autograph model from Dh510,000
Available: Now
Teri%20Baaton%20Mein%20Aisa%20Uljha%20Jiya
THE BIO
Born: Mukalla, Yemen, 1979
Education: UAE University, Al Ain
Family: Married with two daughters: Asayel, 7, and Sara, 6
Favourite piece of music: Horse Dance by Naseer Shamma
Favourite book: Science and geology
Favourite place to travel to: Washington DC
Best advice you’ve ever been given: If you have a dream, you have to believe it, then you will see it.
ALRAWABI%20SCHOOL%20FOR%20GIRLS
COMPANY%20PROFILE
Bahrain%20GP
SPEC%20SHEET%3A%20APPLE%20M3%20MACBOOK%20AIR%20(13%22)
While you're here
Aya Iskandarani: Debates on sovereignty and neutrality alive in Iraq and Lebanon
Robin Mills: Iran's deeper partnership with China is not all that it appears to be
Thomas Harding: US military ready for redeployment of troops to the Gulf
Tips%20for%20travelling%20while%20needing%20dialysis
More from Neighbourhood Watch:
SPECS
Mini John Cooper Works Clubman and Mini John Cooper Works Countryman
Engine: two-litre 4-cylinder turbo
Transmission: nine-speed automatic
Power: 306hp
Torque: 450Nm
Price: JCW Clubman, Dh220,500; JCW Countryman, Dh225,500
UAE%20athletes%20heading%20to%20Paris%202024
Auron Mein Kahan Dum Tha
Starring: Ajay Devgn, Tabu, Shantanu Maheshwari, Jimmy Shergill, Saiee Manjrekar
Director: Neeraj Pandey
Rating: 2.5/5
Listen here
The burning issue
The internal combustion engine is facing a watershed moment – major manufacturer Volvo is to stop producing petroleum-powered vehicles by 2021 and countries in Europe, including the UK, have vowed to ban their sale before 2040. The National takes a look at the story of one of the most successful technologies of the last 100 years and how it has impacted life in the UAE.
Read part four: an affection for classic cars lives on
Read part three: the age of the electric vehicle begins
Read part one: how cars came to the UAE
LIVING IN...
This article is part of a guide on where to live in the UAE. Our reporters will profile some of the country’s most desirable districts, provide an estimate of rental prices and introduce you to some of the residents who call each area home.
COMPANY%20PROFILE
Killing of Qassem Suleimani
National Editorial: Suleimani has been killed, now we must de-escalate
Mina Al Oraibi: Air strike casts a long shadow over the decade ahead
Jack Moore: Why the assassination is such a monumental gamble
Matthew Levitt: Iran retains its ability to launch terror attacks
Hussein Ibish: Trump's order on solid constitutional ground
Simon Waldman: Cautious Israel keeping a low profile
• Remittance charges will be tackled by blockchain
• UAE's monumental and risky Mars Mission to inspire future generations, says minister
• Could the UAE drive India's economy?
• News has a bright future and the UAE is at the heart of it
• Architecture is over - here's cybertecture
• The National announces Future of News journalism competition
• Round up: Experts share their visions of the world to come
Race card
1.45pm: Maiden Dh75,000 1,200m.
2.15pm: Maiden Dh75,000 1,200m.
2.45pm: Handicap Dh95,000 1,200m.
3.15pm: Handicap Dh120,000 1,400m.
3.45pm: Handicap Dh80,000 1,400m.
4.15pm: Handicap Dh90,000 1,800m.
4.45pm: Handicap Dh80,000 1,950m.
The National selections:
1.45pm: Galaxy Road – So Hi Speed
2.15pm: Majestic Thunder – Daltrey
2.45pm: Call To War – Taamol
3.15pm: Eqtiraan - Bochart
3.45pm: Kidd Malibu – Initial
4.15pm: Arroway – Arch Gold
4.35pm: Compliance - Muqaatil
Company%C2%A0profile
The Voice of Hind Rajab
Starring: Saja Kilani, Clara Khoury, Motaz Malhees
Director: Kaouther Ben Hania
Rating: 4/5
Killing of Qassem Suleimani
National Editorial: Suleimani has been killed, now we must de-escalate
Mina Al Oraibi: Air strike casts a long shadow over the decade ahead
Jack Moore: Why the assassination is such a monumental gamble
Matthew Levitt: Iran retains its ability to launch terror attacks
Damien McElroy: A CEO tasked with spreading Iran's influence
Hussein Ibish: Trump's order on solid constitutional ground
Rashmee Roshan Lall: Sound of silence in South Asia