Oil prices have risen sharply and European stock markets have fallen, after the US seizure of an Iranian vessel hit hopes for a peace deal.

Brent crude, the international benchmark for oil prices, rose by as much as 5% on Monday to $95.50 (£70.75) a barrel.

European stock markets dropped, with the UK’s blue-chip FTSE 100 index down 0.5%. The French Cac 40 and the German Dax both fell by about 1%. The Stoxx Europe 600 index, which tracks the biggest companies on the continent, was down 0.9%.

It followed Donald Trump’s announcement on Sunday that an Iranian cargo ship had been seized after trying to get past the US-enforced blockade near the strait of Hormuz shipping channel.

He wrote on social media: “We have full custody of their ship, and are seeing what’s on board!”

The incident raised the possibility that the ceasefire could fail before negotiators reconvened in Pakistan.

The Iran war, which is now entering its eighth week, has killed thousands of people and has rocked the global energy market. Normally about one-fifth of the world’s oil and gas passes through the strait of Hormuz.

Airline stocks also fell sharply on Monday amid fears over the impact on international travel and jet fuel shortages. IAG, the owner of British Airways, dropped 3.4%, while Wizz Air fell 4.9%. Ryanair, Europe’s biggest airline, fell 3.3%. Rolls-Royce, which manufacturers engines for aircraft, also fell by about 3%.

The energy companies BP and Shell were among the biggest risers on the FTSE 100 on Monday, with shares in both up more than 2%.

Oil prices had slumped 9% on Friday, after Iran said it would reopen the strait of Hormuz during the agreed two-week ceasefire period, and Trump said Tehran had agreed to never close the key shipping channel again.

However, over the weekend there were reports that the Iran’s Revolutionary Guards had fired upon commercial vessels.

Tehran has also said it will not participate in a second round of negotiations that the US had hoped to start before the ceasefire expires on Wednesday.

Susannah Streeter, the chief investment strategist at the broker Wealth Club, said hopes for the resumption of trade, especially energy shipments, had “evaporated”, causing “fresh jitters” in the stock market.

“Deep reserves of patience are needed, but with some industries such as airlines staring at jet fuel shortages, these are tense times,” she said.

Fears continue to grow around the scale of the energy shock in the UK, where wholesale gas market prices rose by 5.8% to 102p a therm on Monday.

Analysts at the Energy and Climate Intelligence Unit have estimated that a sustained oil price of $100 a barrel would mean UK motorists who drive 8,000 miles a year could face an increase in annual fuel costs of £140.

The British Oil Security Syndicate, an industry trade organisation, told the Sun there had been a 19% increase in drive-offs and failures to pay at UK forecourts since the start of the US-Israel war on Iran.

There are fears the US blockade could also trigger a fertiliser shortage, one of the vital commodities that normally passes through the strait, in a significant risk for global food security.

Chicago wheat futures rose 1.7% at $6.09-1/4 a bushel on Monday, after a 5% rise last week.