BEIJING - The deadly Paris attacks that killed 129 people and wounded 352 more have sent shock waves across the world as many countries beefed up security and tightened checks on refugees.

The United States, widely accused of having a role in the turmoil in Syria, on Monday subjected Syrian refugees to the most intensive security checks of migrants.

"These refugees are subject to the highest level security checks of any category of traveler to the United States," State Department spokesman Mark Toner told a daily news briefing. "We think we can do this safely and in a way that reflects American values."

Also on Monday, several U.S. governors threatened to stop accepting Syrian refugees as the attacks in Paris raised security worries over Syrian migrants amid concerns that terrorists might use the refugees as cover to sneak across borders.

One of the terrorists involved in Paris attacks was found to have a Syrian passport, and likely entered the country under the cover of refugees, according to French police. 

The Pentagon announced on the same day that it would bolster intelligence sharing with the French military "to the fullest extent allowed by existing law and policy" over a range of shared challenges, said Pentagon spokesman Peter Cook.

Many European countries immediately announced tighter border controls after Friday's attacks in Paris. The moves by the Untied States, which has been reluctant to take Syrian refugees, sent another negative signal over the deteriorating refugee crisis.(Xinhua)