Norway has ignored US calls to isolate Iran, as an Oslo-based solar company agreed a huge energy deal with Tehran on Tuesday.

Solar panel manufacturer Saga Energy said it would invest $2.9 billion in Iran over the next five years, a clear sign to Washington that Norway won't follow President Donald Trump's calls on Western countries to break ties with Tehran."Norway is fully committed to the JCPOA (nuclear deal) and this is proof that we have taken the opening very seriously, and we will see more investment very soon," Norwegian ambassador Lars Nordrum told AFP.

The deal between Saga Energy and Iran's Amin Energy Developers will see two gigawatts of solar panels installed in the country's central desert region.

It is the second largest investment deal in Iran since a landmark 2015 nuclear deal was agreed between Tehran and world powers - including the US - which saw an easing of crippling sanctions on the country.A host of European countries have attempted to strike lucrative deals with Iran once the trade embargo dropped.

The US now appears to be applying pressure on Iran over its ballistic missiles tests which Washington says goes against the nuclear deal.

On Monday, President Donald Trump said he might pull out of the landmark agreement, which would effectively see a recent detente between the US and Iran end.

Iran has welcomed Norway's energy deal with the US at the pivotal time.

"I'd like to thank Norway, which has always been one of the best friends to Iran, for this exciting opportunity," said Saeid Zakeri, head of international affairs for Amin.

Norway's ambassador is also optimistic of improving relations between the two countries.

"We expect there to be some business risk in the Middle East, and Europe stands united in its support of the JCPOA," said Nordrum.  "This is a great win because Iran really needs renewables and this is a new sector for us," he added. 

Norway has already agreed a $1 billion credit line with Iran, with trade ties strengthening between the two countries.