One policeman was killed and four others were injured on Thursday when suspected militants opened fire at them near Tera Khongfangbi in Bishnupur district, about 50 km south of Imphal, officials said.
The condition of one of the injured police personnel is critical, they said.
The incident took place a few km away from Torbung, where the recent violence in the state had first erupted.
Police have launched a combing operation to flush out the militants from the area, the officials said.
Meanwhile, two persons were allegedly abducted by suspected militants in Toribung, a police officer said.
“The duo had gone to fetch foodgrains from their ransacked home when they were abducted. A search operation has been launched to trace them,” he said.
Violent clashes broke out in the northeastern state after a 'Tribal Solidarity March' was organised in the hill districts on May 3 to protest against the Meitei community's demand for Scheduled Tribe (ST) status.
The officials added that curfew has been further relaxed in all the 11 districts where it was clamped, by six hours from the earlier duration of five hours.
The curfew timings vary in these districts.
In another development, 100 trucks travelling from Dimapur to Imphal, carrying essential commodities, were stopped by mobs at different places in North Kangpokpi district, they said.