One year after the United States' assassination of Qassem Soleimani, the former commander of the Quds Force of Iran's Islamic Revolution Guards Corps, a new wave of tension between Washington and Teheran is deepening international concerns.

Sunday marked the anniversary of Soleimani's killing in a drone attack on the Iranian general's convoy near the Iraqi capital of Baghdad on Jan 3 last year. Around the anniversary of the strike, which was ordered by US President Donald Trump, the two sides' rhetoric and military maneuvering targeting each other has made the atmosphere in the Gulf region increasingly combustible.

In the run-up to the anniversary of Soleimani's death, senior Iranian officials have not only reiterated their previously expressed vows to punish the perpetrators behind his assassination, expanding the list of US suspects to 48 names, but also warned the US that someone "from inside your own house" will retaliate for "your crime".

The faceoff between Teheran and Washington was further heightened as Iran told the UN's nuclear watchdog on Friday that it would "produce enriched uranium with 20 percent purity", which it is prohibited from doing under the 2015 Iranian nuclear deal. The US on its part sent a nuclear-powered submarine and two guided missile cruisers to the Persian Gulf and flew B-52 bombers over the Gulf in a show of force. Speculation has been rife that the US might strike Iranian targets.

As such, the US administration shows no signs of dialing down its strategy of exerting extreme pressure on Teheran even though Joe Biden, who has said he supports the US returning to the multilateral nuclear deal, is expected to be sworn in as president on Jan 20.

With Trump using his remaining days in the White House to set up obstacles for his successor, and ramping up confrontation and the use of force that have defined his administration's stance toward Iran, the incoming Biden administration will need to demonstrate strong political will as well as political wisdom if it is to translate words into action and prevent the situation spinning out of control.

In an opinion article published on Sunday in The Washington Post, all 10 living former US defense secretaries warned of the dangers of impeding a full and smooth transition at the Defense Department prior to the Inauguration Day, warning of "international uncertainty about US national security policy and posture".

It will likely be several months before Biden will have the chance to make any major moves concerning Iran, and what those are will no doubt depend on how things develop. Nevertheless, the new US administration should announce it will return to the Iranian nuclear deal at the earliest date to signal to Teheran that it is willing to engage with it.