The prime ministers of Thailand and Malaysia are promising deeper cooperation in an ongoing push against a low-level rebellion in Muslim-majority border regions separating the two Southeast Asian nations.

The pledge came Monday in a meeting outside Kuala Lumpur between Thai Prime Minister Yingluck Shinawatra and her Malaysian counterpart, Najib Razak. Both countries belong to the regional security grouping ASEAN, the Association of Southeast Asian Nations, which is urging Muslim separatists to reject violence and political extremism in southern Thailand.

“Prime Minister Yingluck has requested Malaysia to provide whatever system and cooperation we can to help Thailand in the process towards the long term solutions in the South. We both agreed that this is a domestic matter for Thailand and people in the South must not seek for a separate state, they must reject violence and extremism.''

Ms. Yingluck, on her first visit as prime minister to Muslim-majority Malaysia, praised the mutual help as essential to regional peace.

“We see our cooperation as a key to ASEAN community building, regional connectivity, peace and prosperity. With Malaysia scheduled to be ASEAN chair in the year 2015, Thailand is confident that the launch of ASEAN community will be in a good hand. We look forward to ASEAN being a key driver of economic growth and stability in wider Asia Pacific region.''

Ms. Yingluck's one-day visit came as Thai authorities probe a failed bombing plot in Bangkok involving Iranian suspects and their alleged targets, Israeli diplomats.

Last week, one of two suspects in the alleged plot fled Bangkok to Malaysia, where he was arrested. Malaysian authorities have pledged full cooperation with Bangkok in the probe, but Malaysian police are still holding the suspect as they investigate the case. The second suspect is in Thai custody.