Days after its top nuclear scientist was assassinated, Iran is reportedly boosting nuclear enrichment and threatening to bar inspectors if sanctions on the country are not lifted by February.

Tehran aggressive manouvres will pose an immediate challenge for US President elect Joe Biden who transition team has indicated that the new administration would seek to extend the duration of "restrictions on Iran's production of fissile material that could be used to make a (nuclear) bomb" in a new round of negotiations. 
Iran would also have to address its "malign" regional activities through proxies in Lebanon, Iraq, Syria and Yemen in the talks that would have to include its Arab neighbors like Saudi Arabia, the New York Times cited Biden team members as saying.

However, with Tehran already stating its intention to avenge the killing of nuclear scientist and senior defense official Mohsen Fakhrizadeh last week, that seems unlikely for some time.