Israel unleashed airstrikes across Iran for a third day on Sunday and threatened even greater force as some Iranian missiles evaded Israeli air defenses to strike buildings in the heart of the country.

The two sides were scheduled to meet for a sixth round of negotiations on Sunday. Oman, which was set to host the talks, said on Saturday that this round had been canceled.

The next round of scheduled nuclear talks between the U.S. and Iran will not take place on Sunday, Omanian Foreign Minister Badr Albusaidi announced on Saturday evening, as Israel and Iran continue to trade strikes.