ROME — Italian journalists and lawmakers on Friday protested the wiretapping of reporters’ phone calls during investigations into Libya-based migrant trafficking and humanitarian rescue groups.

Italian daily Domani reported that among the conversations intercepted by investigators a few years ago were journalists for lay and Catholic Italian media and RAI state television.

Primo Di Nicola, a senator from the populist 5-Star Movement who is on a parliamentary oversight commission regarding RAI, said he has proposed a bill to safeguard journalists from the wiretapping of calls with sources.

The investigations date back a few years ago when former Italian government officials were cracking down on humanitarian vessels that were rescuing migrants in the central Mediterranean from traffickers’ unseaworthy boats.

The National Italian Press Federation, a journalists’ union, denounced the wiretapping. It demanded to know who authorized it and said if the aim was to discover reporters’ sources, then journalists’ professional rights were violated.

“It would be very grave, if (the wiretapping) was a way to reveal their sources. Protecting sources is at the basis of journalists’ work,” Di Nicola said.

Domani said hundreds of pages of transcripts of phone conversations are part of an investigation led by prosecutors in Trapani, Sicily, into the activities of humanitarian rescue groups. The transcripts, it said, contain the names of sources and contacts.

There was no immediate comment from Italian prosecutors, who generally don’t speak about ongoing investigations.

Among the intercepted calls was a journalist for the Italian Catholic daily Avvenire who was asking a source how to obtain a video that showed violence against migrants in Libya, a key base for the human smugglers who launch boats crowded with migrants toward European shores.

Many of the traffickers’ flimsy dinghies or dilapidated fishing boats founder or capsize in the sea. In the past several years, rescue vessels operated by humanitarian groups have saved thousands of migrants from drowning.