WASHINGTON — A massive security gap along the nation’s northern border is cause for grave concern as Maine combats a growing drug smuggling trade, says Sen. Susan Collins.

A new federal report highlights just how vulnerable Maine’s long border with Canada is to an array of illegal activity, from the potential of terrorists entering the country to the problem of methamphetamine trafficking, says Collins, R-Maine.

The report by the Government Accountability Office found that the U.S. Border Patrol was able to detect illegal crossings on only a quarter of the 4,000-mile border with Canada – and that authorities possessed an “acceptable level of security” over 32 miles of the lengthy stretch from Washington state to Maine.

Those gaps exist despite the Department of Homeland Security spending nearly $3 billion last year on northern border security measures – and making 6,000 arrests and intercepting 40,000 pounds of illegal drugs across that border.

The findings show the need for much more coordination between federal, state and local authorities, reported the GAO, Congress’ investigative arm.

“I am gravely concerned about the findings in this report,” said Collins, who along with other top members, Republicans and Democrats alike, of the Senate Homeland Security and Governmental Affairs Committee requested the federal investigators look into the state of northern border security. The committee released the report this week.

With budgetary constraints preventing the Border Patrol from spreading more officers across the border, the Department of Homeland Security “must continue to analyze the right mix of resources, ensuring there is effective use of personnel, technology, and international, state, and local agency partnerships that allow the border be open to our friends, but closed to those who would do us harm,” Collins said in a statement. “These illegal crossers include individuals seeking to illegally immigrate, criminals trafficking humans and smuggling drugs and, potentially, terrorists.”

Collins has been focused on the problem of the so-called crystal meth trade across Maine’s more than 600-mile border with Canada. She was a co-sponsor of a bill signed into law recently by President Barack Obama that requires the Office of National Drug Control Policy to develop a new counter-narcotics strategy for dealing with the northern border, including figuring out how to achieve better coordination between various law enforcement agencies.

Collins said last month, after Obama signed the bipartisan legislation, that the new law requires authorities to draw up a plan that reflects “the unique nature of small communities along the border.  The challenges faced by the rural Maine towns along our 611-mile border with New Brunswick and Quebec are vastly different from those faced by such cities as Buffalo, Detroit, or Seattle.”

Collins wrote in a column in January that two Maine federal judges raised concerns about an “alarming increase in drug smuggling across the Canadian border” when she met with them in December 2009. She noted that a recent federal report found that Maine has the highest percentage in the nation of residents being treated for addiction to prescription painkillers.

Other senators also criticized the state of northern border security. Sen. Joe Lieberman, I-Conn., the chairman of the Homeland Security Committee, said, “These findings should sound a loud alarm to the Department of Homeland Security, the Canadian government, and our committee. The American people are grossly under-protected along our northern border.”

Democratic Sen. Carl Levin of Michigan said in a statement that “any failure to coordinate efforts between agencies that weakens security on the northern border is totally unacceptable.”

A spokesman for the Department of Homeland Security said the federal agency already is working on a plan to address some of the concerns raised by the GAO report.

The Department of Homeland Security has been working to make “critical security improvements along the northern border, deploying additional Border Patrol agents, technology and infrastructure,” said Adam Fetcher, a DHS spokesman.

DHS also is working on the issue of working together with other agencies and law enforcement authorities to “improve coordination of northern border enforcement activities,” Fetcher said.