US Markets

Wall Street to take stock of Syria airstrikes

Wall Street looked set to open lower again on Tuesday, with U.S. stock index futures and European markets subdued after the U.S. announced it had launched airstrikes in Syria.

The bombing began at approximately 8:30 p.m. ET on Monday.This is the first time the U.S. and Arab allies have carried out airstrikes against Islamic State (also known as ISIS) militants in Syria.

A number of second-tier data releases are due on Tuesday in the U.S., led by the flash Manufacturing PMI for September. This may be slightly better than the three-year high of 57.9 recorded last month, and follows disappointing reading for the euro zone earlier in the day.

Read MoreEuro zone business activity hits 9-month low

Another manufacturing survey will come from the Richmond Federal Reserve, and is also expected to remain elevated.

There will also be the latest FHFA house price index, which comes after the National Association of Realtors reported on Monday that sales of previously owned homes declined 1.8 percent last month.

On the policy side, Minneapolis Fed Governor Narayana Kocherlakota gave a dovish speech late on Monday, in which he said inflation was expected to be below target for the next few years and the current jobless rate (of 6.1 percent) overstated the strength of the labor market.

On Tuesday, there will also be a number of Fed speakers making appearances, including voting member Jerome Powell.

CarMax and Carnival will post results before Wall Street opens on Tuesday, to be followed by Bed Bath & Beyond after the close of trade.

Early on Tuesday, shares of AstraZeneca and Shire slipped by 5.1 percent and 6.6 percent respectively on the London Stock Exchange after the U.S. Treasury looked set to scupper deals involving the two pharma companies. The Treasury announced action on Monday against tax inversions—when a company buys a foreign firm in order to switch its headquarters to a country with lower tax rates.

U.S. companies that have been accused of attempting inversions include Medtronic,which announced it would buy Dublin's Covidien in June, and Chiquita Brands,which is attempting to buy Ireland's Fyffes.

Pfizer attempted a deal with AstraZeneca earlier this year, but the talks stalled after significant opposition arose.

Read MoreTreasury takes actions to deter tax inversions