Two rockets struck separate targets on Wednesday in oil fields just outside Basra, not far from the headquarters of many international and domestic oil companies.

Though a bit more frequent in recent weeks, rocket attacks have been rare since the Islamic State was pushed out of Iraq more than 18 months ago, and oil fields generally have not been targets. Basra, in southwestern Iraq just above the Persian Gulf, is one of the richest oil production regions in Iraq.

In the first attack, three employees of an Iraqi drilling company who were injured when a Katyusha rocket hit their sleeping quarters were taken to a hospital, said Khalid Hamza, the deputy director of the Basra Oil Company, an Iraqi firm.

There were no injuries reported in the second attack. No other details were available about the strike, and officials would not say who they believed was responsible for the attacks.

The rocket strikes come as tensions are escalating between the United States and Iran after attacks on oil tankers in the Gulf of Oman, for which Washington blamed Tehran. Iran said on Monday that it would soon breach curbs on its stock of low-enriched uranium set out in the 2015 pact limiting its nuclear program. In response, President Trump ordered an additional 1,000 troops to the Middle East and affirmed his pledge that Iran would not be allowed to develop a nuclear weapon.

Iraqi soldiers near the entry to the Zubair oil field on Wednesday after a rocket struck a building housing several oil companies.CreditEssam Al-Sudani/Reuters

Iraqi soldiers near the entry to the Zubair oil field on Wednesday after a rocket struck a building housing several oil companies.CreditEssam Al-Sudani/Reuters

The Trump administration withdrew the United States from the nuclear pact last year and has reimposed painful economic sanctions on Iran, including a prohibition on oil exports that has cut off a large portion of its government’s revenue.

Western analysts have described the attacks on the oil tankers as an effort by Iran to signal that if it is blocked from selling its oil, it will penalize the rest of the world by making the shipment of oil riskier and more expensive.

Recent rocket attacks in Iraq have included one in the Green Zone, home to the embassies of the United States and other countries. Other strikes appeared to take aim at Iraqi security forces.

The Iraqi government has been resolute about keeping out of any conflict between Iran and the United States.

“We think its an operation that aims to drag Iraq into the crisis between Iran and America and to involve Iraq in a war,” said Gen. Yahya Rasool of the Baghdad Joint Command, which includes American and Iraqi forces.

The first rocket landed before dawn Wednesday near the Zubair oil field in an area that includes the headquarters of many oil companies, including those of Shell and Exxon Mobil; the second landed in the area of the Rumaila oil field, one of Iraq’s oldest and largest oil patches, where BP is operating. Shell said in a statement that all its staff members were accounted for and that the company was continuing normal operations in Iraq.

Abbas Maher, the mayor of Al Zubair, said the first rocket had been launched from his town.

“This is the first incident of its kind, and we consider it as targeting an Iraqi company and damaging the Iraqi economy,” Mr. Maher said.