Media playback is unsupported on your device Media caption Rupert Wingfield-Hayes says little re-building has been done in some areas

Services have been held in Japan to mark the devastating earthquake and tsunami that struck two years ago.

Ceremonies took place in the three worst-hit prefectures and a minute's silence was observed at 14:46 (05:46 GMT), when the quake hit.

More than 18,000 people were left dead or missing in the disaster, which also caused the Fukushima nuclear crisis.

Since then, most of Japan's nuclear reactors have remained off, amid impassioned debate over nuclear energy.

At a service of remembrance in Tokyo, Japanese Emperor Akihito spoke in praise of the survivors and relatives of the dead.

"I am always deeply moved by seeing how so many people lead their daily lives without complaining," he said. "[I hope] to be able to share their suffering, if only a little."

Prime Minister Shinzo Abe, who also attended the memorial service, pledged to accelerate reconstruction work.

"Japan will never experience a true spring if spring does not come to north-eastern Japan. I promise never to forget the weight of each day and promise to speed up the reconstruction of the region," he said.

"I will make Japan a country resilient to disasters while standing on the side of people who were affected."

Growing frustration

The government has channelled billions of dollars into reconstruction, and Mr Abe has made a point of frequently visiting affected regions.

What I want most is to have my home again Migaku Suzuki

However, the ceremonies held along Japan's north-east coast today were still being held in the middle of wastelands, and there is growing frustration at the slow pace of reconstruction, the BBC's Rupert Wingfield-Hayes in Tokyo reports.

"What I want most is to have my home again," Migaku Suzuki told journalists in the port city of Rikuzentakata.

Tens of thousands of people remain displaced in the north, after entire communities were washed away or felled.

According to an official tally, 15,881 people died in the disaster and 2,668 others remain unaccounted for.

Police in Miyagi were still continuing their search for missing persons, news agency AFP reported.

"We haven't found any bodies for a year," officer Toshiaki Okajima told AFP. "But there are still 1,300 missing people in Miyagi alone and the feelings of families haven't changed. That's why the police need to keep looking for remains."

The nuclear issue, meanwhile, remains the subject of public concern.

On Sunday, thousands of people marched in Tokyo urging an end to the use of nuclear power. Japan's 50 nuclear reactors were shut down for checks after the earthquake and only two have since been turned on again.

But Mr Abe, who was elected in December, has indicated he wants to restart the reactors after safety checks to meet pressing power needs.

About 160,000 people had to be evacuated from the area around the nuclear plant, where meltdowns occurred at three reactors after tsunami waters knocked out cooling systems. It remains unclear if they will ever be able to return.