TEHRAN, April 20 (Xinhua) -- Iran's Foreign Minister Seyed Abbas Araghchi said Monday that U.S. "provocative actions" and ceasefire violations are major obstacles to continuing peace negotiations between the two countries.

During separate phone calls with his Pakistani and Russian counterparts, Araghchi condemned U.S. actions against Iranian commercial shipping, including the reported seizure of the container vessel Touska and its crew, and cited "contradictory positions and rhetoric of threat" from Washington, according to a Foreign Ministry statement.

A ceasefire that took effect on April 8 after 40 days of fighting remains fragile. Pakistan has mediated indirect talks between Tehran and Washington, hosting a first round in Islamabad on April 11 and 12, but Iran has not confirmed participation in another round.

Iran's semi-official Tasnim news agency reported that Tehran's attendance depends on Washington meeting preconditions. It cited a U.S. naval blockade and "excessive demands" as key obstacles.

Araghchi said Iran would decide whether to continue diplomacy based on "all aspects of the issue" and U.S. behavior, adding that Tehran would take steps to protect its interests and national security.

Tensions follow joint U.S.-Israeli attacks on Tehran and other Iranian cities beginning Feb. 28, which killed Iran's then-Supreme Leader Ali Khamenei, senior commanders, and civilians. Iran responded with waves of missile and drone strikes targeting Israel and U.S. assets in the Middle East. ■