The deal will see the gradual integration of Kurdish forces and administration into the Syrian state.
Kurdish-run prisons hold about 8,000 suspected IS fighters and around 34,000 of their family members in camps.
Tehran has threatened to treat an attack by the US as part of last summer's war, and its response could be more dramatic.
The multiparty system had been "promoting division among citizens", the country's interior minister said.
US First Lady Melania Trump and her husband President Donald Trump have walked the black carpet at the premier of her new documentary.
Iran seized the oil tanker with 18 crew members, including 16 Indians, in December alleging it had illegal diesel.
The move follows Donald Trump's previous claim the US was taking the crucial Panama canal "back" from China.
Sir Keir Starmer's visit to China brought agreements on visas, services, healthcare, green tech and finance.
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