Tens of thousands of people have gathered in St Peter's Square for an Easter Mass led by Pope Francis.
Journalists at a major Chinese paper, Southern Weekly, have gone on strike in a rare protest against censorship.
The row was sparked last week when the paper's New Year message calling for reform was changed by propaganda officials.
Staff wrote two letters calling for the provincial propaganda chief to step down. Another row then erupted over control of the paper's microblog.
Supporters of the paper have gathered outside its office, reports say.
Some of the protesters carried banners that read: "We want press freedom, constitutionalism and democracy".
Police did not interfere with the protesters outside the paper's offices, according to reports.
"The Nanfang [Southern] Media Group is relatively willing to speak the truth in China so we need to stand up for its courage and support it now," Ao Jiayang, one of the protesters, told Reuters news agency.
Southern Weekly is perhaps the country's most respected newspaper, known for its hard-hitting investigations and for testing the limits of freedom of speech, says the BBC's Martin Patience in Beijing.
Chinese media are supervised by so-called propaganda departments that often change content to align it with party thinking.
The row erupted after a New Year message which had called for guaranteed constitutional rights was changed by censors into a piece that praised the Communist Party.
In response, the newspaper's journalists called for the Guangdong propaganda chief's resignation, accusing him of being "dictatorial" in an era of "growing openness".
In two open letters 35 prominent former staff and 50 interns at the paper demanded Tuo Zhen step down, saying the move amounted to "crude" interference.
On Sunday night, a message on the newspaper's official microblog denied that the editorial was changed because of censorship, saying that the "online rumours were false".
The microblog updates, said to have been issued by senior editors, sparked the strike among members of the editorial team who disagreed with the move, reports say.
Almost 100 editorial staff members have gone on strike, saying the newspaper is under pressure from authorities.
"Not since the time of reform and opening up and the founding of China has there been someone like Tuo Zhen," Yan Lieshan, a retired Southern Weekly editor, also told Reuters.
It is thought that this is the first time that there has been a direct showdown between newspaper staff and party officials, our correspondent adds.
In an editorial on Friday referring to the row, the state-run newspaper Global Times said: "The reality is that old media regulatory policies cannot go on as they are now. The society is progressing, and the management should evolve."
However it also pointed out that "no matter how the Chinese media is regulated, they will never become the same as their Western counterparts".
"The only way that fits the development of Chinese media is one that can suit the country's development path," it said.
Searches for "Southern Weekly" on the Twitter-like weibo were blocked on Monday, according to reports.
Some influential Chinese journalists have had their social media accounts deleted in recent weeks, Agence-France Presse news agency says.
When asked about the issue with Southern Weekly at a regular press briefing last week, a foreign ministry spokeswoman said that is "no so-called news censorship in China".
How the case is handled is seen as a key test for Chinese officials, installed just two months ago in a once-in-a-decade leadership transition, observers say.