The United States has threatened to fine US companies that take part in an Arab lead economic boycott of Israel.
"The US government is strongly opposed to restrictive trade practices or boycotts targeted at Israel," said Undersecretary of Commerce for Industry and Security Kenneth Juster.
The economic boycott of Israel is a peaceful, legal and noble means of struggle against the enemy and is aimed at preserving security and peace
"The Commerce Department is closely monitoring efforts that appear to be made to reinvigorate the Arab boycott of Israel and will use all of its resources to vigorously enforce US anti-boycott regulations."
Mr Juster's threat came after 18 of the 22 members of the Arab League agreed to "reactivate" a half-century-old ban on trade with Israel last week.
US laws ban the participation by US nationals and companies in unsanctioned foreign government trade boycotts, especially the Arab League's boycott of Israel.
The Department of Commerce has issued more than m (£16.7m) in fines and turned down export licences to those found violating the law.
"It is necessary to reactivate the Arab boycott of Israel and combat the importation of Israeli products to Arab countries," said the League after a meeting of the Boycott Office of Israel (BOI).
League members Egypt, Jordan and Mauritania - which maintain diplomatic ties with Israel - and Somalia did not attend the meeting.
"The economic boycott of Israel is a peaceful, legal and noble means of struggle against the enemy and is aimed at preserving security and peace," the League said in a statement after the meeting.
Most Arab countries softened their stance after the Gulf War 10 years ago and the launch of the Middle East peace process.
The BOI met again for the first time in eight years last October, when it drew up a list of 15 firms to be black-listed, but the list remained unpublished.
The next meeting will take place in the Syrian capital, Damascus, in April