BRUSSELS, July 26 (Reuters) - Qatar has threatened to

cut gas supplies to the European Union in response to the bloc's

due diligence law on forced labour and environmental damage, a

letter from Qatar to the Belgian government, seen by Reuters,

showed.

Qatar is the world's third-largest exporter of liquefied

natural gas (LNG), after the United States and Australia. It has

provided between 12% and 14% of Europe's LNG since Russia's 2022

invasion of Ukraine.

In a letter to the Belgian government dated May 21, Qatari

Energy Minister Saad al-Kaabi said the country was reacting to

the EU's corporate sustainability due diligence directive

(CSDDD), which requires larger companies operating in the EU to

find and fix human rights and environmental issues in their

supply chains.

"Put simply, if further changes are not made to CSDDD, the

State of Qatar and QatarEnergy will have no choice but to

seriously consider alternative markets outside of the EU for our

LNG and other products, which offer a more stable and welcoming

business environment," said the letter.

A spokesperson for Belgium's representation to the EU

declined to comment on the letter, which was first reported by

German newspaper Welt am Sonntag.

The European Commission also received a letter from Qatar,

dated May 13, a Commission spokesperson told Reuters, noting

that EU lawmakers and countries are currently negotiating

changes to the CSDDDD.

"It is now for them to negotiate and adopt the substantive

simplification changes proposed by the Commission," the

spokesperson said.

Brussels proposed changes to the CSDDD earlier this year to

reduce its requirements - including by delaying its launch by a

year, to mid-2028, and limiting the checks companies will have

to make down their supply chains.

Companies that fail to comply could face fines of up to 5%

of global turnover.

Qatar said the EU's changes had not gone far enough.

In the letter, Kaabi said Qatar was particularly concerned

about the CSDDD's requirement for companies have a climate

change transition plan aligned with preventing global warming

exceeding 1.5 celsius - the goal of the Paris Agreement.

"Neither the State of Qatar nor QatarEnergy have any plans

to achieve net zero in the near future," said the letter, which

said the CSDDD undermined countries' right to set their own

national contributions towards the Paris Agreement goals.

In an annex to the letter, also seen by Reuters, Qatar

proposed removing the section of CSDDD which includes the

requirement for climate transition plans.

Kaabi is also chief executive of QatarEnergy.

Qatar Energy gas has long-term supply contracts with major

European companies, including Shell, TotalEnergies

and ENI.