"The rate of killing and disappearance in Jaffna showed no sign of letting up," the Tamil Tigers' peace secretariat said on its website, listing the names of 30 people, most of them listed as "shot and killed."
Government troops control Jaffna, but the rebels have cutoff the northern coastal enclave from the rest of the island for two months since fighting closed the main A9 highway stranding residents and blocking supplies.
The government announced Wednesday that it had airlifted hundreds of tons of goods to the area this week.
But the pro-rebel Tamilnet.com website has warned of a "humanitarian crisis" as food and other supplies run out in Jaffna, and said the town remains a "boiling pot" amid increasing violence against civilians.
The warning came as negotiators from the government and the Liberation Tigers of Tamil Eelam (LTTE) traveled to Geneva for weekend peace talks, which it is hoped will end the recent violence.
Around 3,000 people have been killed in 10 months of fighting,