The PM will meet leaders including US President Joe Biden over the weekend, before Monday's service.
Although she met Mr Biden when she was foreign secretary, this weekend's meeting with him will be Ms Truss's first as UK prime minister.
Ms Truss will also attend the UN General Assembly in New York next week, where further meetings with global leaders are expected. The meeting with Mr Martin comes at a time of strained relations with the EU over post-Brexit checks in Northern Ireland. Syria, Venezuela, Afghanistan, Myanmar, Russia and Belarus have not been invited - whilst Iran, North Korea and Nicaragua have been asked to only send a senior diplomat.
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