WASHINGTON--President Reagan moved yesterday to ban all U.S. imports from Iran, citing "the continued and increasingly bellicose behavior" of Ayatollah Ruhollah Khomeini's government in the Persian Gulf.

Reagan also said he was directing the departments of State and Treasury to bring about a ban on the export to Iran of 14 broad categories of U.S. products "with potential military application."

The punitive economic measures follow the military retaliation Reagan ordered last week against Iran after a Silkworm missile strike against a U.S.-flagged Kuwaiti oil vessel in Kuwaiti waters.

"These measures will remain in place so long as Iran persists in its aggressive disregard for the most fundamental norms of international conduct," the president said in a statement.

Reagan had been weighing the moves for several days after a team of advisers in both the national security and economic areas had recommended them.

Secretary of State George P. Shultz said, meanwhile, he hoped other countries would follow the U.S. lead and embargo Iranian oil, thereby causing a drop in the price of Iranian oil and in revenue for the purchase of weapons.

"Maybe it will be catching," Shultz said on the "MacNeil-Lehrer News Hour."

Shultz acknowledged it would be difficult to enforce the U.S. embargo, since the origin of oil on world markets is hard to trace. But, he said, "while Iran is conducting the war (with Iraq) and conducting terrorism, we shouldn't be buying things from them to the tune we are.... We feel it's important to lay down our marker."

In ordering the bans, Reagan was using authority granted him by Congress under a section of the International Security and Cooperation Development Act.

White House spokesman Roman Popadiuk said oil imports from Iran last year were around $500 million, and had reached about $900 million by the end of July 1987.

Non-petroleum imports from Iran in 1986 were valued at around $100 million, he said, and he added, "We expect that number would have declined by 25 percent in 1987, even with no trade controls in place."

According to the Energy Department's "Monthly Energy Review," Iranian oil in 1986 accounted for 0.31 percent of U.S. oil imports. For the first seven months of 1987, the percentage was 1.4.

Total U.S. exports to Iran amounted to roughly $34 million, said Popadiuk. "That number is declining in 1987. Those U.S. exports covered by the new controls amount to less than $10 million," he said.

In announcing the moves, Reagan said he had consulted with Congress in advance.

He said, "The measures I am directing are a direct result of the Iranian government's own actions, including its unprovoked attacks on U.S. forces and U.S. merchant vessels."

Reagan also cited as reasons for his moves Iran's "refusal to implement U.N. Security Council Resolution 598, its continued aggression against non-belligerent nations of the Persian Gulf and its sponsorship of terrorism there and elsewhere in the world."

The president said the ban on imports will take effect "as soon as possible" and said the additional controls on exports "will go into effect in a week to 10 days."

"Let me emphasize that we are taking these economic measures only after repeated but unsuccessful attempts to reduce tensions with Iran and in response to the continued and increasingly bellicose behavior of the Iranian government," he said.