Oil prices rallied on Monday amid tensions over the disappearance of a Saudi Arabian journalist, which stoked crude supply worries.

U.S. President Donald Trump said on Monday that he will send Secretary of State Mike Pompeo to Saudi Arabia over the disappearance of the journalist.

Jamal Khashoggi, a journalist and columnist for The Washington Post, has been missing since he entered the Saudi Consulate in Istanbul on Oct. 2.

Earlier last week, Trump said during an interview that he will impose severe punishment if Saudi Arabia is confirmed to be behind Khashoggi's alleged death.

Saudi Arabia on Sunday strongly warned against any threats to exert economic sanctions or political pressure on the kingdom, saying it will respond to any action with greater action as the kingdom plays an influential and vital role in the regional and global security and economy.

The West Texas Intermediate for November delivery rose 0.44 U.S. dollar to settle at 71.78 dollars a barrel on the New York Mercantile Exchange, while Brent crude for December delivery added 0.35 dollar to 80.78 dollars a barrel on the London ICE Futures Exchange.