Washington: An Islamist group calling itself Al Nusra Front has claimed responsibility for 12 attacks targeting Syrian security forces and pro-government thugs, the SITE Monitoring Service said on Saturday.

In two communiques posted on Friday on jihadist websites, the group said the series of assassinations and bombings in June and July took place in the capital Damascus and in Aleppo, according to SITE.

The claimed attacks, listed in the messages, include the kidnapping and killing of a soldier whose cell phone’s memory card had images that “indicated his participation in oppressing and killing Sunnis”.

Another involved the assassination of a barber over his “cooperation with the security to oppress protesters and putting up a checkpoint in his neighbourhood.”

The group’s announcement came as hundreds of soldiers backed by helicopter gunships attacked Khirbet Ghazaleh in the province of Daraa — the cradle of a 16-month uprising — amid heavy gunfire, the Syrian Observatory for Human Rights said.

The violence followed an international outcry over the killing Thursday of more than 150 people in the central village of Tremseh.

With circumstances surrounding the incident still unclear, United Nations observers made their way to the village on Saturday to investigate.

Rights activists say the Syria conflict has cost more than 17,000 lives since the uprising began in March 2011.