Kuala Lumpur - Thick smoke blanketed several states in Malaysia Thursday after winds brought in choking haze caused by forest fires on Indonesia's neighbouring Sumatra island.

In the southern state of Malacca, visibility was 6 kilometres while visibility at the international airport in the northern state of Penang was recorded at 8 kilometres by midafternoon, with an air-pollutant index of less than 100, which qualifies for moderate air quality, the Meteorological Department said on its website.

A department spokesman said the haze was expected to continue until the end of the week, adding that residents were encouraged not to carry out open burning to help improve air quality.

Thick smoke from forest fires has blanketed a number of cities in Riau province on Sumatra because of increasing open burning. (dpa)