The State Department said Friday there is "concrete evidence" of Libya's continued support for terrorism and pointed to Libyan links to a surge in attacks against Americans and western Europeans.

"It is a situation we are looking at carefully - how serious it is and what steps we need to take," department spokeswoman Phyllis Oakley said.She referred to a series of arrests of members of the Japanese Red Army, who apparently have been trained in the Middle East and supplied with arms and explosives that came via Libya. One of the alleged Japanese terrorists was arrested along the New Jersey Turnpike with bomb-making materials.

In a statement that officials said was carefully prepared and worded, Oakley said, "There is concrete evidence, including the seizure of Libyan arms destined for the Irish Republican Army and the arrest in Senegal of Libyan operatives, that Libya continues its support for terrorism."

"There has also been an upsurge in recent weeks of terrorist attacks against U.S. and western European interests in Europe, Latin America and Africa."

She said, "Although these incidents are still under investigation, in numerous cases the prime suspects are groups which have received support from Libya."

The largest seizure of arms came last November when a boat loaded in a Libyan port was found to be carrying 150 tons of weapons bound for the IRA. Two Libyan agents, carrying bomb-making equipment, were arrested in Dakar, Senegal, in February.

Oakley and other State Department officials refused to speculate on what measures the United States might use if the evidence emerges to definitely link the Libyan government to recent attacks against American targets in the Sudan and India.

In April 1986, U.S. bombers struck Libyan targets, including the capital, Tripoli, after U.S. intelligence intercepted telephone calls that linked the Libyan government to an attack on a West Berlin discotheque that killed two American servicemen.