Iran’s hostile messages to the United States reached new heights last Thursday when an American spy drone was shot down by the Islamic Revolutionary Guard Corps over the Persian Gulf. In Saudi Arabia, meanwhile, facilities were hit by ballistic missiles fired by Houthi rebels in Yemen loyal to Iran.

The Iranians say the advanced U.S. surveillance aircraft, which is capable of staying in the air for more than 30 hours and is equipped with sophisticated observation systems, was downed because it had infiltrated Iranian airspace. This claim contradicts the statement issued by the U.S. military that the drone was shot down in international airspace. Regardless, the incident illustrates Iran’s determination to continue provoking the United States despite its stated desire to avoid war.

Iran’s escalation in the Persian Gulf has been gradual. The six attacks on oil tankers in or near the Strait of Hormuz since May were specifically designed to avoid leaving fingerprints. In the wake of the drone incident, however, the chief of the IRGC was quick to threaten the U.S., saying it should “not to cross the red line.” Thursday’s missile, fired at an obvious American target, was a more direct message to the White House.

Tehran has decided to push the envelope in the Persian Gulf for two main reasons. One pertains, of course, to its domestic situation. Iran is seeking to create a new equation whereby the tighter the noose of U.S.-imposed economic sanctions, the greater the risk of a conflagration in the Gulf. Conversely, if the United States decides to loosen the noose, perhaps Iran will be more amenable to talking.

The other reason behind Iran’s escalation in the Gulf stems from the belief in Tehran that the White House is so afraid of conflict and military quagmire in the Gulf that it won’t rush to retaliate—even against more severe provocations. This assessment was strengthened not only by U.S. President Donald Trump’s stated desire to avoid war with Iran but also his tempered response to the oil tanker attacks.

In formulating their assessment, the Iranians are also leaning on the opposition within the United States to deploying additional forces to the Persian Gulf, Trump’s fundamental desire to withdraw from the Middle East, his recently launched re-election campaign, and on the fact that his acting defense secretary is stepping down. Ayatollah Ali Khamenei and his advisers believe that under these circumstances, Iran now has a decent chance of stinging the United States without getting stung back.

Are the Iranians wrong? The IRGC chief pointed to Tehran’s red lines by downing the American drone, but it isn’t clear he knows what Trump’s red lines are. Is Washington still preparing its response to the drone incident, or will it only respond with military force if a manned plane is hit?

What is clear is that the situation in the Persian Gulf is highly combustible, and both sides are closer to conflict than to dialogue and negotiations over a new nuclear deal.

This column first appeared in Israel Hayom.