The rate of UK economic growth affects things like pay increases and the amount of tax raised.
The chancellor was speaking at the end of the International Monetary Fund meeting in Washington.
The chancellor's criticism follows a report that the conflict will hit the UK harder than other big economies.
A subdued economy makes trade-offs and choices over public spending more difficult, Chris Mason writes.
The chancellor says the US president does not have a "clear plan" to exit the conflict.
The chancellor tells the BBC it is "too early" to say exactly who would get help but hinted any support would not arrive until the autumn.
After the government's pledge to invest £2bn into quantum computing, how is the industry feeling?
Chancellor Rachel Reeves announced changes to cash Isa rules, but what are they and how do they work?
The chancellor must react in real time to the economic shock of the war in Iran, writes the BBC's political editor.
