WASHINGTON — State Department officials said Monday that the maximum pressure campaign on Iran will intensify in 2020, as the U.S. seeks to rein in Tehran's pursuit of nuclear infrastructure and regional aggression.

"There will be more sanctions to come, and Iran's economic problems and challenges are going to compound in 2020," a senior State Department official said Monday on a call with reporters. "They are already deep into a recession, and we are also seeing Iran come under greater diplomatic isolation."

Another senior State Department official added that the Trump administration has sanctioned approximately 1,000 individuals and entities with links to Iran's malign activities.

"What we are doing is denying the regime the revenue that it needs to run an expansionist foreign policy, and by that policy, Iran has less money to spend today than it did almost three years ago when we came into office," the official said.

The latest revelation comes on the heels of Sunday's U.S. military airstrikes in Iraq and Syria against an Iranian-backed militia group.

President Donald Trump ordered the "precision defense strikes" on five Kata'ib Hizbollah facilities following a string of attacks on Iraqi military bases that host American troops. On Friday a U.S. civilian contractor was killed in a rocket attack on an Iraqi base near Kirkuk.

Earlier this month, Secretary of State Mike Pompeo blamed Iranian-backed forces for a series of attacks on bases in Iraq and warned that any future attacks on Americans or U.S. allies would be "answered with a decisive U.S. response."

"As long as its malign behaviors continue, so will our campaign of maximum pressure," Pompeo said during a Dec. 11 press conference at the State Department.

Pompeo then announced another round of fresh sanctions on Tehran, this time targeting Iran's largest shipping company and biggest airline, saying the companies are aiding the Iranian regime's alleged proliferation of weapons of mass destruction.

Iranian President Hassan Rouhani said in response that Tehran will overcome U.S. sanctions.

"The government is determined to defeat (the enemy) by bypassing America's sanctions ... or through various means including talks," the semi-official Iranian news agency ISNA quoted Rouhani as saying.

Tensions between Tehran and Washington have soared following Trump's withdrawal from the landmark Iran nuclear deal brokered by the Obama administration.

The landmark 2015 nuclear agreement lifted sanctions on Iran that crippled its economy and cut its oil exports roughly in half. In exchange for sanctions relief, Iran accepted limits on its nuclear program and allowed international inspectors into its facilities.

The relationship between the U.S. and Iran took another anxious turn following a string of attacks in the Persian Gulf this summer.

In June, U.S. officials said an Iranian surface-to-air missile shot down an American military surveillance drone over the Strait of Hormuz. Iran said the aircraft was over its territory.

That strike came a week after the U.S. blamed Iran for attacks on two oil tankers in the Persian Gulf region and after four tankers were attacked in May.

The U.S. in June slapped new sanctions on Iranian military leaders blamed for shooting down the drone. The measures also aimed to block financial resources for Iran's Supreme Leader Ayatollah Ali Khamenei.

Tensions soared again in September when the U.S. blamed Iran for the strikes in Saudi Arabia on the world's largest crude-processing plant and oil field.

The predawn attack forced the kingdom to shut down half its production operations. The event triggered the largest spike in crude prices in decades and renewed concerns of a budding conflict in the Middle East. Iran maintains that it was not behind the attacks.