WARSAW, Poland (AP) — Poles demonstrated nationwide Tuesday against a bill widely viewed as a effort by the country’s nationalist ruling party to silence an independent, U.S.-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. In practice, it would push American company Discovery Inc. to sell its controlling stake in TVN, a network with many channels that operates the all-news station TVN24 and has a flagship evening news program watched daily by millions.

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 United States, a key ally.

Poland's ruling party, Law and Justice, has long sought to nationalize the media, claiming it is for national security reasons. It says the law would bring Poland into line with other European countries, including France and Germany, which limit foreign ownership in the media. It cites the risk of media being controlled by hostile powers like Russia and China.

Prime Minister Mateusz Morawiecki said Tuesday the law isn't directed against anyone but seeks to protect Polish society, alleging that foreign entities are trying to influence Poland's debate on COVID-19 vaccinations.

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

Large crowds chanted “Free media!” in dozens of cities and towns in support of TVN. In front of parliament in the capital of Warsaw, Donald Tusk, a former top European Union official who is now the leader of the opposition party Civic Platform, described free media as a pillar of democracy worth fighting for and accused the government of trying to “return to communist patterns.”

On Wednesday parliament is set to debate and vote on the bill.

The bill was introduced last month and appears to have a high chance of passing. Jaroslaw Gowin, who heads a small party in Poland's right-wing coalition government, opposed the bill and was dismissed from the government just as the protests started Tuesday.

Reporters Without Borders urged Polish lawmakers to reject the legislation, accusing the ruling party of targeting the independent broadcaster “to enable government allies to acquire TVN.”

Poland fell this year to 64th 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. Discovery had already felt endangered as the National Broadcasting Council, a Polish state body, has so far failed to renew the broadcast license for TVN24, which expires in September.

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 situation in Hungary, where authoritarian Prime Minister Viktor Orbán has gained near-total control over the media as private outlets have either folded or come under the control of his allies.

Poland's ruling party has already turned tax-funded public TV into a party mouthpiece. Lately it has been seeking greater control over private media, with the state oil company buying a large private media group last year.

TVN represents the largest-ever U.S. investment in Poland. The company was bought for $2 billion by another U.S. company, Scripps Networks Interactive, which was later acquired by Discovery.

Last week a bipartisan Congressional group expressed its increasing concern “about the ongoing attacks on the free press, independent judiciary and the rule of law in Poland.”

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

Jean-Briac Perrette, president and CEO of Discovery International, called the planned vote on the bill concerning, warning that “an unpredictable regulatory framework should be very concerning for all potential investors in the market.”

The development comes as Discovery is set to merge next year into a mega-company with AT&T’s WarnerMedia.

Vanessa Gera, The Associated Press