WASHINGTON (Reuters) - Some U.S. Republicans sought to use a must-pass spending bill on Monday to block President Barack Obama’s plan to accept thousands of Syrian refugees, saying the Paris attacks had proven they pose too much of a threat to the United States.

Abu Ahmad's sons prepare bamboo sticks they collected for their father to build a temporary summer room within a refugee camp that was formerly the Zeyzoun Vanguards summer camp for school children, in Zeyzoun village, Deraa region, Syria, August 6, 2015. REUTERS/Alaa Al-Faqir

Republican Representative Brian Babin circulated a letter asking that lawmakers include a provision in the spending bill to defund the plan to admit 10,000 Syrians this year.

“The terrorist attack in Paris by militant Islamists is a loud clanging alarm bell to Congress and the American people warning us why we must block Obama’s reckless and foolish plan,” Babin said.

By Monday, 14 members of the House of Representatives, all Republicans, had signed the letter. Babin planned to collect signatures until Friday.

Several Republican congressional committee chairmen called for the program’s suspension on Monday. Over a dozen state governors, almost all Republicans, refused to allow Syrian refugees into their states.

Many Republicans, who control both the House and Senate, had objected to Obama’s plan before Paris.

Senator Chuck Grassley wrote to Senate Appropriations leaders weeks ago asking that funding for resettling Syrians be restricted until Obama offered a plan for screening them.

“We cannot tell who among the thousands of Syrian refugees that the administration wishes to settle here are terrorists,” he said in a Senate speech on Monday.

Obama reiterated his commitment to accepting the 10,000 on Monday.

While dozens of Republicans opposed Obama’s plan, only a few Democrats backed it. “When the world is experiencing a refugee crisis of a magnitude not seen since the end of World War Two, are we to abandon allies and partners awash with refugees and refuse to do our part?” Representative Adam Schiff asked.

Congressional aides are negotiating the $1 trillion-plus spending bill, facing a Dec. 11 deadline to avoid a government shutdown.

A House Appropriations spokeswoman declined comment on what might end up in the legislation. A Senate Appropriations spokesman said Paris had heightened interest in the issue and the committee would address it in the coming weeks.

It was not clear that a provision barring Syrians would be legal. The Immigration Act of 1965 banished national origin quotas, such as measures that once barred most immigrants from Asia.

“Barring refugees based on nationality raises serious questions regarding national origin discrimination and sets a dangerous precedent,” said Tom Jawetz, the liberal-leaning Center for American Progress’ vice president for immigration policy.