Poland's security services say a Chinese businessman and a Polish man, both employed in telecoms, have been arrested for spying.
Chinese tech giant Huawei is at the centre of several diplomatic rows, most spurred by concerns over security.
Under Chinese law, firms are compelled to "support, co-operate with and collaborate in national intelligence work".
Its media-shy founder, Ren Zhengfei, is also a former engineer in China's army and joined the Communist Party in 1978.
As a result, critics argue China may be using Huawei as a proxy to help hack attacks, eavesdrop on conversations or gain high-level access to sensitive networks.
New Zealand, Australia and the US have all barred the company from involvement in their national 5G networks.
"Despite efforts in some markets to create fear about Huawei and to use politics to interfere with industry growth, we are proud to say that our customers continue to trust us," said Ken Hu, the company's rotating chief executive and deputy chair.