New York Times News Service

WASHINGTON — The Trump administration began an urgent debate Friday over how to respond to what officials say has grown into a shadow war with Iran, after attacks on oil tankers in the Persian Gulf that appeared meant to assert Iranian control over one of the world’s most strategic shipping lanes at a time of heightened tension with the United States.

President Donald Trump put Iran on notice that the United States would push back but offered no details and suggested that he was ready to engage with the Iranians, who denied responsibility for the attacks, whenever they are prepared to talk.

But tension remained high, with a senior official confirming that Iran had fired a surface-to-air missile Thursday at a U.S. drone flying over the Gulf of Oman, where the attacks on the tankers occurred. The episode took place that morning, between the distress calls from the two ships crippled by explosions that day.

Officials at the Pentagon weighed tactical responses to the attacks, like beefing up the security around tankers, or more drastic moves, like deploying as many as 6,000 Navy, Air Force and Army personnel to the Persian Gulf.

One of the two tankers hit by the explosions Thursday, the Japanese-owned Kokuka Courageous, was being towed into a port in the United Arab Emirates for further inspection. The Navy dispatched a bomb squad team to investigate.

The other tanker, the Norwegian-owned Front Altair, remained adrift, on fire and abandoned by its crew after Iranian patrol boats chased off civilian tugs that had come to tow it to port.