Terex Corp's sale discussions with China's Zoomlion are continuing despite concerns a deal could be blocked by the Committee on Foreign Investment in the United States (CFIUS), according to people familiar with the matter.

CFIUS, set up by the US government to scrutinize deals that could pose national security threats, has been increasingly flexing its muscle amid intensifying Chinese interest in foreign investments. Earlier this month, it forced Philips to scrap a $3.3. billion sale of its lighting business to a consortium backed by Chinese investors.

Terex, a Westport, Connecticut-based crane maker, has 97 so-called priority-rated contracts with the US government that could attract CFIUS scrutiny. It also provides mobile harbor cranes in ports that are seen as a critical part of US infrastructure.

"Dubai Ports (World) pales in comparison to the potential security issues involved" with a potential Zoomlion merger with Terex, Michael Wessel, a member of the US-China Economic and Security Review Commission, tweeted on Wednesday.

Dubai's DP World dropped a deal to manage six US ports in 2006 following U.S. political backlash.

While Terex's board has yet to decide on whether it should abandon an agreed sale to Finland's Konecranes in favor of Zoomlion's $3.3 billion unsolicited proposal, it is not treating CFIUS as an issue that would preclude any deal with Zoomlion, the people said this week.

The value of Terex's priority-rated government contracts is very small and not material to Terex's business, according to the sources.

The company's ports business in North America is also small, with its biggest contract being a $75 million order for automated equipment at the Long Beach port in California, the sources added.

The sources asked not to be identified because the deliberations are not public. Terex declined to comment, while a Zoomlion spokesperson was not immediately available for comment.

Port equipment accounted for 11 percent of Terex's sales in 2014, according to its latest annual report.

Terex already has a Chinese competitor operating in US ports, Zhenua Port Machinery (ZPMC).

Zoomlion has offered $30 per share in cash for Terex, versus the 0.8 Konecranes shares for each Terex share that its shareholders stand to receive as a result of the deal that was agreed in August. Terex shares ended trading in New York on Thursday at $22.

Terex has to pay Konecranes a $37 million termination fee under its merger agreement if its board changes its recommendation on the deal.

A deal for Terex would stretch Zoomlion's balance sheet and may spur it to seek backing from the Chinese government, William Blair equity analysts wrote in a research note on Jan 26. This could increase CFIUS scrutiny of the deal. Zoomlion is partly owned by the Chinese province of Hunan.

On Wednesday, Konecranes Chairman Stig Gustavson questioned how Zoomlion would finance a transaction and whether it could get a deal with Terex approved by US authorities.