* Attacks follow rejection of insurgent group's offer of talks
* Long-running southern insurgency has killed more than 6,500
By Patpicha Tanakasempipat and Panarat Thepgumpanat
BANGKOK, April 20 (Reuters) - A string of gun and grenade attacks in southern Thailand that killed two people reflects tension over talks aimed at ending violence there, a conflict monitoring group said on Thursday, warning against similar attacks in future.
Thailand's far south has battled a separatist insurgency since 2004, when resistance to Buddhist rule in the Muslim-majority region flared. More than 6,500 people, most of them civilians, have died in separatist violence since.
Eight people were wounded in 13 incidents on Wednesday across the provinces of Narathiwat, Pattani and Songkhla, near Thailand's border with Malaysia. No group has yet claimed responsibility.
The attacks follow the Thai government's rejection of a conditional offer for peace talks made this month by one of the main insurgent groups, the Barisan Revolusi Nasional (BRN).
The violence was the BRN's way of showing it is capable of coordinated strikes as a way to push for peace talks, said Srisompob Jitpiromsri, head of independent monitoring group Deep South Watch.
"This reflects attempts to create conditions for peace talks in the future," Srisompob, whose group tracks violent incidents in the region, told Reuters.
"The group is expected to carry out similar attacks periodically, which will likely affect peace dialogues in the long run."
A Thai security official blamed the attacks, which targeted security forces and civilians on "people who want to cause chaos", but did not single out the BRN.
"It looks like their intention wasn't to kill, but rather to cause disorder," Colonel Yutthanam Petchmuang, a spokesman for the Internal Security Operations Command, told Reuters.
The violence followed coordinated attacks in the region on April 7, just hours after King Maha Vajiralongkorn signed into law a new constitution, as a step towards ending military rule.
The new constitution, which critics say will entrench military rule in Thailand, was widely opposed in the south.
"The BRN is showing that it is the right negotiating partner, which can control and command the fighters on the ground," Rungrawee Chalermsripinyorat, an independent researcher who monitors the conflict, told Reuters.
Talks between the government and a handful of shadowy insurgent groups began in 2013, under the democratically-elected government of Prime Minister Yingluck Shinawatra, overthrown in 2014 by the military in the name of ending political turmoil.
In February, the government said it had reached a breakthrough pact with MARA Patani, an umbrella group that says it speaks for insurgent groups in the south. Analysts say only a handful of BRN members belong to the group, however.
The provinces of Narathiwat, Pattani and Yala formed part of an independent Malay Muslim sultanate before being annexed by Thailand in 1909. (Editing by Amy Sawitta Lefevre and Clarence Fernandez)