New Delhi, July 22 -- Haze from forest and peatland fires in some parts of Indonesia's Sumatra island was detected in Malaysia on Sunday, officials said.

Forest and peat fires are an annual problem in Indonesia that strain relations with neighboring countries. In recent years, smoke from the fires has blanketed parts of Indonesia, Singapore, Malaysia and southern Thailand.

A number of areas in Indonesia's Riau province were still covered by thick haze, although choking smoke had not been registered in the provincial capital of Pekanbaru, said Riau deputy police chief Adrianto Jossy Kusumo.

He said more than 140 forest and peatland fires were reported in the province. Rokan Hilir and Rokan Hulu districts were the worst hit areas by fire...