Adds shares in paragraph 4, CFO comment in paragraph 2

By Jesus Calero

May 6 (Reuters) - Danish wind turbine maker Vestas VWS.CO reported an unexpectedly large first-quarter profit rise on Wednesday as it ramped up production for the offshore sector, but warned of geopolitical and tariff-related risks.

"Last year in Q1 we hadn't put a single one of our new offshore turbines up," Vestas Chief Financial Officer Jakob Wegge Larsen told Reuters in an interview.

"What we really see in Q1, in the revenue increase, is that the offshore ramp-up is progressing positively. We are now installing and manufacturing offshore turbines at a significantly higher level compared to last year," he added.

Shares in Vestas were 1.5% higher at 0849 GMT, helping their year-to-date gain to 13.4%.

Vestas has been aiming to sell more to offshore power developers, but high costs have held back manufacturing. After struggling with supply chain disruptions, high offshore ramp-up costs and other cost inflation, it is now seeking to boost margins despite U.S. wind policy and tariff uncertainty.

The Danish company repeated guidance from February for a full-year operating margin before special items of 6% to 8% on sales of between 20 billion and 22 billion euros. In 2025, the margin was 5.7% on sales of 18.8 billion euros.

Vestas said the outlook forecast was based on the assumption that the geopolitical environment does not significantly change business conditions.

"We achieved the highest first-quarter profitability since 2018," said Vestas CEO Henrik Andersen in a statement, adding that geopolitical uncertainty and the energy crisis "underline the need for affordable, secure, and sustainable energy".

Vestas reported an increase in order intake, to 4.50 gigawatts (GW) from 3.14 GW, although this was slightly less than analysts had expected.

In the first quarter, operating profit before special items was 127 million euros ($149 million) against a year-earlier 14 million and a mean forecast of 71 million in an analyst poll shared by Vestas. The margin widened to 3.2%.

Turnover in the quarter, the sector's seasonally slowest, increased 14% to 3.97 billion euros, slightly above expectations, as sales of offshore turbines picked up.

Vestas also announced a new 100 million euro share buyback programme.

($1 = 0.8524 euros)