(Reuters) -China has instructed state-owned firms to pause new deals with businesses linked to Hong Kong billionaire Li Ka-shing and his family after his plan to sell two ports in Panama to a BlackRock ( BLK )-led consortium, Bloomberg News reported on Thursday.

CK Hutchison ( CKHUF ), the telecoms-to-retail conglomerate owned by Li, has been caught in China's crosshairs in the highly politicised deal with the U.S. firm.

The Hong Kong-based company this month agreed to sell most of its global ports business, including assets near the strategically important Panama Canal, in a deal that would garner the firm more than $19 billion in cash.

The directive was issued to state-owned enterprises last week at the behest of senior officials, Bloomberg reported, citing people familiar with the matter. Existing tie-ups are not affected.

The report added Chinese regulators are also reviewing what investments the family has in China and abroad in a bid to better understand the breadth of their business dealings.

Shares of CK Hutchison Holdings ( CKHUF ) rose 1.2% by noon, down from a gain of as much as 3.6% earlier in the day.

Over the past two weeks, pro-Beijing Hong Kong newspaper Ta Kung Pao has published a series of commentaries criticising the deal for harming China's national interests and depicting it as a betrayal of China.

China's Hong Kong and Macau Affairs Office reposted some of the commentaries on its website, which fuelled speculation Beijing could take steps to try to scupper the sale.

Chinese regulators, under the instructions of central leadership, have begun looking into the deal, a source has told Reuters, a sign of Beijing's discontent with CK Hutchison's ( CKHUF ) divestment under perceived U.S. pressure.

U.S. President Donald Trump has hailed the transaction after previously calling for the Panama Canal to be removed from what he deemed to be Chinese control.

(Reporting by Surbhi Misra in Bengaluru and Clare Jim in Hong Kong; Editing by Christian Schmollinger and Sonali Paul)