1. Dollar under pressure: The U.S. dollar has dropped to its lowest level in seven months against a basket of currencies.

The dollar has now lost all of its post-inauguration gains. And there is still plenty for investors to worry about.

Former FBI director James Comey will testify before the Senate intelligence committee on Thursday about an investigation into possible coordination between President Trump's campaign and Russian officials.

The uncertainty doesn't stop there: British voters will head to the polls on Thursday in a crucial general election that will take place days after a major terror attack in London.

A dramatic rift between some of America's closest allies in the Gulf has added to worries.

2. Oil prices drop: U.S. crude futures dropped 0.6% on Tuesday to trade around $47.20 per barrel.

The move extends losses posted on Monday after six countries including Saudi Arabia cut off diplomatic relations with Qatar over what they claim is its support for terrorism. Qatar described the allegations as "baseless" and "unjustified."

Qatar is a member of OPEC, and investors are worried that the crisis may dent the cartel's determination to eliminate a supply glut.

3. Global market overview: U.S. stock futures edged down early on Tuesday.

European markets opened around 0.5% lower.

Asian markets ended the session mixed. Markets in Shanghai and Hong Kong closed higher, while Japan's Nikkei shed nearly 1%.

The Dow Jones industrial average and the S&P 500 both lost 0.1% on Monday. The Nasdaq closed down 0.2%.

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4. Earnings and economics: Lands' End (LE) is set to release earnings before the open Tuesday, while Dave & Busters (PLAY) will follow after the close.

The JOLTS report on jobs openings is set to be released at 10 a.m. ET.

Kevin Hassett, nominated to lead the White House Council on Economic Advisers, will be questioned by the Senate Banking Committee at 10 a.m.

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5. Coming this week:

Tuesday - Lands' End earnings
Wednesday - House budget hearing on Trump's economic policies; House debates Dodd-Frank reforms overhaul; U.S. crude inventories data; Australia Q1 GDP data; China foreign exchange reserves data
Thursday - Yahoo shareholders vote on Verizon deal; U.S. Treasury Secretary Steven Mnuchin meets with House members over debt ceiling; Former FBI director Jim Comey to testify before Senate; Dell earnings; U.K. election; China trade data
Friday - Tim Cook delivers MIT commencement speech