At least seven people have been injured after unknown attackers threw grenade on a nightspot in Wajir town in northeastern Kenya.

North Eastern Provincial Commissioner James Ole Serian confirmed the incident on Saturday night which he said took place at Ngamia Club in Wajir.

"Unknown attackers threw a grenade on Ngamia nightclub and so far seven people have been injured from the attack. We have not established the identities of those injured nor the attackers," Ole Serian told Xinhua by telephone.

He said the police have launched investigations to establish the motive behind the attack which came amid heightened security around the country.

The country's security agencies are at an unprecedented state of alert amid the latest reports that Al-Shabaab have planned attacks against Kenya and U.S. interests in the country.

Kenyan forces are hunting down the Al-Shabaab militants inside Somalia to stop further incursions into Kenya. The east African nation blames a series of grenade attacks and kidnappings on Somali Al-Shabaab.

The militia group, which is aligned to al-Qaeda network, has said before that it would attack Kenya.

Kenya has in the recent admitted that the threat of terror attacks targeting the country remains real but has moved to assure that security personnel are on high alert.

The last few weeks have seen Kenya suffer incursions by the Al- Shabaab militia from neighboring Somalia with heavy fighting reported near the border town of Mandera.

Kenya's border with Somalia has been officially closed since January 2007, but civilians fleeing the upsurge in fighting between the Transitional Federal government of Somalia and the Al- Shabaab militia in south-central Somalia have been arriving in Kenya in rising numbers.

The enhanced security comes amid reports that Al-Shabaab, blamed for a series of abductions on Kenyan soil, has dispatched bomb makers and assassins to eliminate Defense Minister Yusuf Haji and National Assembly Deputy Speaker Farah Maalim.

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 group by capturing their military bases and killing scores of them.