Italy's former Prime Minister Matteo Renzi has received an anonymous envelope containing two bullets, members of his Italia Viva (IV) party said on social media.
The news has been widely condemned by Italian politicians, including the League and Five Star Movement, who have expressed their opposition to threats against politicians.
"It is time to say enough to this politics of violence and hatred," said Teresa Bellanova, Deputy Minister and member of IV.
"Matteo, we are at your side, with strength and pride, we will not be intimidated," she added on Facebook.
The President of the Chamber, Maria Elisabetta Alberti Casellati, also telephoned the former Prime Minister to express her solidarity.
"Political dissent, even if bitter, cannot and must never transcend into threats and violence," added government minister Mara Carfagna on Twitter.
Renzi posted on Facebook following the outpouring of support online, saying: "Thank you all. Let us move forward together with freedom and courage."
He served as Italy's Prime Minister from 2014 to 2016 and remains in the Senate as the leader of IV, a small splinter group of the centre-left Democratic Party.
In January, his party's decision to leave the country's coalition government forced the resignation of former Prime Minister Giuseppe Conte and sent Italy into a political crisis.
A new government was formed by former President of the European Central Bank, Mario Draghi, to avoid an early election during the COVID-19 pandemic. However, Renzi's popularity has suffered as a result, according to recent polls.
The politician was also heavily criticised for travelling to Saudi Arabia in January and holding a meeting with Crown Prince Mohammed bin Salman.
A US intelligence report found that bin Salman had likely approved an operation to kill or capture Saudi journalist Jamal Khashoggi inside the Saudi consulate in Istanbul in October 2018.
Renzi responded to criticism by saying that it is "fair and necessary" to maintain good relations with Saudi Arabia.
Other politicians in Italy, including former prime ministers Silvio Berlusconi and Mario Monti, have previously received anonymous parcels containing bullets.