SEOUL, South Korea — The United Nations Security Council has announced new measures against North Korea, blacklisting 27 ships, 21 shipping companies and one individual accused of helping the North evade previous sanctions.

The move increases pressure on the North ahead of planned summit meetings between its leader, Kim Jong-un, and the presidents of South Korea and the United States.

The oil tankers and cargo ships on the list, announced on Friday, were banned from ports worldwide or will have their assets frozen, and the shipping companies will face an asset freeze. Most of those named had also been blacklisted by the United States Treasury in February.

In response to North Korea’s rapid acceleration of its nuclear and missile programs, the Security Council has adopted a series of sanctions resolutions in recent years. The toughest, last year, banned key North Korean exports like coal, seafood and textiles, and drastically reduced the amount of petroleum the North was allowed to import.