Australia's Prime Minister Tony Abbott (L) and Malaysia's Prime Minister Najib Razak tour the tarmac of RAAF Base Pearce with Australian Air Force Group Commander Craig Heap (3rd R) and Commodore Peter Leavy (2nd R), commander of join task force 658, near Perth on Thursday. Najib visited the Australian search base for missing Malaysia Airlines Flight MH370 as a nuclear-powered submarine joined the near-four week hunt that has so far failed to find any sign of the missing airliner and the 239 people on board. Photo: Reuters
Malaysia will not give up on the search for missing flight MH370, its prime minister said as he visited the search hub in Perth.
Prime Minister Najib Razak's comments came at a joint news conference with Australian leader Tony Abbott.
Najib praised the search effort, saying the co-operation amid "great tragedy" had "given us all heart".
The Malaysia Airlines plane disappeared on 8 March en route from Kuala Lumpur to Beijing. It was carrying 239 people.
Planes and ships have been scouring the southern Indian Ocean, where the jet is believed to have crashed.
The focus of the search is a 221,000 square kilometres (85,000 square mile) area 1,500km (932 miles) west of Perth.
But so far not a single piece of debris from the Boeing 777 has been found.
Najib met search crews at Pearce RAAF base near Perth today morning, before their planes left for the day, and then later held talks with Abbott.
"The disappearance of MH370 has tested our collective resolve," he told a news conference.
"Faced with so little evidence, and such a Herculean task, investigators from Malaysia, the US, the UK, China, Australia and France have worked without pause to reveal the aircraft's movements."
He thanked both search teams and the Australian government for their efforts in recent weeks, and said the search would go on.
"I know that until we find the plane, many families cannot start to grieve. I cannot imagine what they must be going through. But I can promise them that we will not give up," he said.
Malaysian authorities have come in for heavy criticism over their management of the search, especially from relatives of the plane's 153 Chinese passengers.
Today eight military planes and nine ships were due to take part in the search.
Weather conditions were fair, with visibility of approximately 10 kilometres (6 miles), JACC said.
The British submarine HMS Tireless is also in the southern Indian Ocean and is due to be joined by Royal Navy ship HMS Echo.
The Australian Navy ship Ocean Shield is heading to the region and has equipment for detecting the plane's "black-box" flight recorder.
Experts say timing is critical as the flight recorder may only have enough battery power to send out a signal until 7 April.
On Wednesday Malaysian police chief Khalid Abu Bakar said investigators had "cleared" all passengers of possible involvement in hijacking, sabotage or having personal or psychological problems that could have been connected to the disappearance.
But he said that the criminal investigation could "go on and on and on. We have to clear every little thing".
"At the end of the investigations, we may not even know the real cause. We may not even know the reason for this incident," he added.
The police chief said that more than 170 interviews had been conducted with family members of the pilots and crew members, and that even cargo and food served on the plane were being investigated in case of sabotage.