Demonstrations are taking place across Poland against a bill widely viewed as a effort by the country’s nationalist ruling party to silence an independent US-owned television broadcaster that is critical of the government.

Technically, the bill would prevent non-European owners from having controlling stakes in Polish media companies, but in practice, it would push Discovery to sell its controlling stake in TVN, a network with many channels that operates all-news station TVN24 and has a flagship evening news programme that is watched by millions daily.

At stake in the bill’s passage is Poland’s reputation for media freedom and as a place for foreign companies to do business. The proposal is already straining relations with the US, a key ally.

Poland’s ruling Law and Justice party has long sought to nationalise the media, citing national security, and says the law would bring Poland into line with other European countries, including France and Germany, which limit foreign ownership in the media sector.

It cites the risk of media being controlled by hostile powers like Russia and China.

Prime Minister Mateusz Morawiecki said the law is not directed against anyone but seeks to protect Polish society. He alleged, for example, that foreign entities are trying to influence Poland’s public debate on Covid-19 vaccinations.

“It is through the media that other countries influence our social life,” he said at a news conference.

Demonstrations in support of TVN began in several cities and towns a day before parliament is set to debate and vote on the bill.

The bill was introduced last month. Its chance of passing is high but not certain because Jaroslaw Gowin, a vice prime minister who heads a small party in Poland’s right-wing coalition government, views the bill as an attack on pluralism.

Mr Morawiecki dismissed him from the government just as the protests were starting on Tuesday.

Reporters Without Borders urged legislators to reject the legislation.

It accused Law and Justice of “targeting Poland’s leading independent TV broadcaster on the pretext of combating disinformation and defending national security”.

The press freedom group said it believes the true aim is “to enable government allies to acquire TVN”.

Poland fell this year to 64th out of 180 countries in the group’s World Press Freedom Index, its lowest-ever ranking. It was in 18th place in 2015, the year Law and Justice took power.

TVN24 is the leading source of independent broadcast news for many Poles, and celebrated the 20th anniversary of its launch on Monday.

The bill’s fate is being watched as a key test of media freedom and democracy.

Critics fear it would be a large step bringing Poland closer to the media landscape in Hungary, where authoritarian Prime Minister Viktor Orban has gained near-total control over the media as private outlets have either folded or come under the control of his allies.

TVN represents the largest US investment in Poland. The company was bought for 2 billion dollars by another US company, Scripps Networks Interactive, which was later acquired by Discovery.

Former Polish foreign and defence ministers wrote an open letter to the government last week expressing fears the proposed legislation could weaken ties with the US, which has troops stationed in Poland and sells the country military equipment.