Washington / Riyadh / Tehran (dpa) - With new allegations and the threat of tightened sanctions, the US has fueled tensions with Iran.

US Secretary of State Mike Pompeo accused the leadership in Tehran on his trip to Jeddah of attacking important oil installations in Saudi Arabia last Saturday in a "warlike act". US President Donald Trump said Wednesday on Twitter that he had instructed the Ministry of Finance to "significantly" strengthen the sanctions against Iran.

The Iranian government on Wednesday again denied any responsibility for the attacks on oil facilities in Saudi Arabia, to which the Tehran-backed Houthi rebels in Yemen had come to prominence. Iranian Foreign Minister Mohammed Jawad Sarif accused the US government on Wednesday of escalating its "economic war against the Iranians" with new sanctions. Sarif spoke on Twitter of illegal and inhuman "economic terrorism".

At first, Trump made no statement as to which penalties should be tightened. The US government has already imposed extensive sanctions on Iranian banks, oil and gas companies, the country's arms program, and government and military officials. At the weekend, Trump had threatened with retaliatory attacks after the attacks on Saudi Arabia.

First, it was unclear whether the announcement of new sanctions against Iran would make a US military response less likely. Pompeo advised on Wednesday with the Saudi Crown Prince and Defense Minister Mohammed bin Salman about a reaction. The two, according to the US State Department, agreed that the international community must come together to address the continuing threat of "the Iranian regime." They agreed that "the Iranian regime must be held accountable for its continued aggressive, reckless and threatening behavior."

Pompeo said on his trip to Saudi Arabia: "That was an Iranian attack." The Houthi rebels in Yemen, who claimed to be attacked last Saturday, described Pompeo as a "liar." The intelligence agencies were "very confident" that the Iran-backed Houthi rebels did not have the weapons systems used in the attacks. Both the United States and Saudi Arabia would address the attacks in the general debate of the UN General Assembly next week. Later, Pompeo tweeted that the US was on the side of Saudi Arabia. "The Iranian regime's threatening behavior will not be tolerated." On Thursday Pompeo wanted to travel to Abu Dhabi for talks in the United Arab Emirates.

Even a Saudi military spokesman made Iran responsible for the attacks. Iran is "undoubtedly behind the attacks," Turki al-Malki said in Riyadh. In the attack on the oil refinery in Abkaik a total of 18 drones were used in the attack on the oil plants in Churais a total of seven cruise missiles. Investigations had shown that the rockets could not have been fired from Yemen, but had come from the north. Northern neighbors of Saudi Arabia are Iraq and Iran.

Saudi Arabia's Crown Prince and Defense Minister Mohammed bin Salman described the attack as a test of the will of the international community to respond to acts that threaten international security and stability. This was reported by the Saudi state news agency SPA.

Saudi Arabia will not receive weapons and other armaments from Germany for another six months. The Federal Government extended the export ban, which has been in effect since November 2018, until Wednesday, March 31, 2020. Until then, no new arms deals with Saudi Arabia will be approved, and the delivery of already approved exports will remain blocked.

Since Trump's unilateral termination of its nuclear deal with Iran over a year ago, tensions between Washington and Tehran have continued to grow. The US wants to use harsh sanctions and a policy of "maximum pressure" to persuade Iran to agree to a new treaty with stricter conditions and stop supporting terrorist groups in the region.

The US sanctions hit Iran's important oil and gas production hard and triggered an economic crisis. With its back to the wall, however, Iran wants to start up its nuclear program again. Recently, there were also more incidents in the important for the oil transport road of Hormuz. The US has strengthened its military presence in the region.