Campaigners to free captured Israeli soldier Gilad Shalit blocked entry to the Hadarim prison near Netanya on Tuesday in an attempt to prevent mothers of Palestinian inmates visiting their sons.
Angry altercations broke out between several visitors and activists, who urged the inmates' relatives to pressure Hamas for a prisoner swap deal with the Israeli government.
Some mothers voiced support for the campaign, however.
"We want our sons to be released and the prisoner Gilad Shalit to be set free and returned home," one said.
A bus carrying the visitors eventually entered the jail after a short delay.
Tuesday's demonstration is the second in a wave of events planned by activists, who last week protested outside the prime minister's residence in Jerusalem.
This latest push to free Shalit comes after Mahmoud al-Zahar, a Hamas leader in Gaza, said last week that negotiations for a prisoner exchange were in a "deep freeze" following the assassination on January 19 of a senior Hamas man in Dubai, for which the organization blames Israel.
"We want to kick-start the process and avert a situation in which talks freeze and we lose Gilad," said Yoel Marshak, a representative of the kibbutz movement and one of the campaign's organizers.
On Friday protesters will congregate at Prime Minister Benjamin Netanyahu's private home in Caesarea, he said.
Shalit's family is not taking part in the events but are said to have given their approval.