The nuclear crisis has escalated in Japan. Critical work to reconnect power lines at the crippled Fukushima plant was stalled on Monday after smoke rose from two reactors, fuelling fears of fresh radiation leaks. Tokyo Electric Power Company, TEPCO, which operates the plant, said work to connect power cables to No. 3 and No. 4 reactors was halted after smoke belched from the buildings of No. 2 and No. 3 reactors. TEPCO said it had briefly evacuated its workers after grayish and blackish smoke was spotted at the No. 3 reactor above a pool storing spent nuclear fuel. Japan's Nuclear and Industrial Safety Agency Spokesman Hidehiko Nishiyama said that the causes of the smoke remain unknown and that work to resuscitate power and cooling systems at the troubled reactors will be delayed. Yukiya Amano, Director General of the International Atomic Energy Agency said that the situation at the Fukushima plant remains serious. High levels of radioactive substances have been detected in seawater near the Fukushima power plant. TEPCO said, the substances were detected in seawater which was sampled on Sunday about 100 metres south of the Fukushima plant. Meanwhile, the death toll from the double disaster and the number of those reported missing touched almost 22,000.