Japanese Prime Minister Naoto Kan said in a nationally televised press conference Friday that the situation at the Fukushima No. 1 nuclear plant remained severe and appealed for continued solidarity among the people in overcoming the disaster.

The premier said that the workers at the stricken plant 240 kilometers north of Tokyo were putting their lives on the line in carrying out emergency work.

One week after the massive magnitude 9.0 earthquake rocked northeastern Japan and ensuing tsunami claimed the lives of 6,911 people, Kan told the nation he was convinced that Japan would overcome its biggest crisis in post-war days, despite the current situation being "grave."

"We don't have any room to be pessimistic or be discouraged. We don't have the room to do so," the prime minister said, adding that he was certain Japan would be able to rebuild itself from scratch and called for the nation to "not be discouraged."

While he said the situation at the stricken nuclear power plant in Fukushima Prefecture remains severe and uncertain, the prime minister vowed that he would do "everything in his power" to overcome the earthquake and nuclear crisis.

The premier praised the people of Japan for acting in a "calm manner" following the triple-whammy of disasters, but called for the ongoing cooperation of prefectural heads and citizens in areas surrounding the worst-affected regions in accommodating the burgeoning numbers of displaced evacuees.

National public broadcaster NHK reported that there are more than 280,000 refugees staying at 2,200 emergency shelters in eight prefectures -- including the worst-hit Miyagi, Fukushima and Iwate -- many of which are running low on critical supplies such as fresh water, power, food, blankets and medicine.

The colossal quake struck at 2:46 p.m. (0546 GMT) last Friday, with the epicenter at 130 km of the coast of Miyagi Prefecture at a depth of 24.4 kilometers under the seabed.

The quake triggered a deadly tsunami with waves up to 10 meters high sweeping inland as far as 10 km.