WAJIR, Kenya - At least four Kenyans were seriously injured in the latest twin grenade attacks in Wajir town in northern Kenya on Wednesday evening, police said.

Divisional police commander James Mutungi said unknown people hurled grenades at a Ralph Super Cut barbershop and a Roho Safi Hotel in the latest attacks by suspected Al-Shabaab militia from neighboring Somalia.

Mutungi said the incidents occurred at about 8:30 pm (1730 GMT). The scenes of attacks are about 300 meters apart, he said.

"We still don't know the people behind this incident but it is still early to speculate," Mutungi told Xinhua by telephone from Wajir town.

He said at least two people were injured in the barbershop incident. The injured were rushed to the local district hospital. Two others were injured in the hotel.

The incident comes as police have particularly warned against the laxity in the screening of cars for explosives at all shopping malls and any business or social gatherings with at least 10 people at any given moment that these might be vulnerable to attacks.

The East African nation has also been plagued by a spate of grenade and landmine attacks in its northern region where  the insurgents have  killed more than 20 police officers and over 30 civilians.

Since the Kenya military incursion into Somalia several attacks believed to have been carried out by Al-Shabaab have occurred in Mandera, Wajir, and Garissa and Dadaab districts of northern Kenya even as the military reports gains against the Islamist group by capturing their military bases and killing scores of them.

Al-Shabaab militants have vowed to attack Kenyan towns after the east African nation invaded Somalia to flush out the insurgents it blamed for kidnappings of tourists.