A.P. Moller-Maersk missed first-quarter profit expectations on Thursday and warned that political and trade tensions clouded the outlook, sending shares in the world’s biggest container shipper sharply lower.

Earnings before interest, tax, depreciation and amortisation (EBITDA) for the three months to March 31 rose 5 percent to $669 million but came in well below the $852 million forecast by analysts in a Reuters poll.

Chief Executive Soren Skou called the result “unsatisfactory” but said he still expects EBITDA for the year at $4-$5 billion.

Maersk shares fell 11 percent to 9,016 Danish crowns by 0811 GMT, near their lowest in 18 months, although quarterly revenue at $9,253 million topped analysts’ forecasts of $8,755 million.

Analysts at Jefferies said disappointment stemmed in part from “relatively sluggish underlying volume growth” of 2.2 percent, short of an expected increase of 3-4 percent.

Container freight rates rose 7 percent, but the cost of shipping a container increased even more, partly as a result of higher oil prices, Skou said.

Skou in previous quarters played down the risk of a global trade war hurting its business but noted “increased uncertainties due to geopolitical risks and trade tensions.”

“We have to admit that the Americans have taken a number of initiatives recently that have caught us by surprise,” Skou told Reuters in an interview.

“The (trade) situation has become more intense,” he said, adding it would hurt Maersk’s business if trade talks between the United States and China end in failure.

“The whole situation regarding Iran, which is pushing oil prices up, is certainly also not good for our container business,” Skou said.

He added that Maersk is winding down its business in Iran following new U.S. sanctions: “I don’t know the timing details exactly, but I am certain that we’re also going to shut down (in Iran).”

After a slump in shipping and oil, Maersk is restructuring and divesting its energy businesses – including oil exploration, oil tankers and supply services – to focus on shipping, ports and logistics.

Skou said he would implement short-term initiatives to improve profitability and lower unit costs, including taking out container capacity.

Rival German container shipping line Hapag-Lloyd reported higher first-quarter profits on Monday.

Maersk shares are down 29 percent from a July 2017 peak when optimism about freight rates and a turnaround in global container shipping began to fade.