Iran’s oil exports dropped by around 42 percent in early October amid fears surrounding Israeli strike threats likely targeting Iranian oil sites, according to Oil&Gas.

Tanker tracking firm data indicated that Iranian oil exports fell to 600,000 barrels of oil loaded per day in the first 10 days of the month, rather than the average 1.4 million barrels per day seen in recent months.

Israeli Prime Minister Benjamin Netanyahu has vowed Iran will “pay for” its strike on Israel on October 1, when Iran fired approximately 180 missiles, according to Reuters. Israel is rumored to be considering attacking Iran’s oil sites.

Newsweek reached out to the Iran Ministry of Petroleum for comment via email.

Satellite imagery recently showed oil tankers vacating the waters surrounding Kharg Island, Iran’s main oil terminal, which some fear may be Israel’s target, according to CNBC.

Iranian oil exports are expected to remain lower throughout this month and reach a maximum of 1.35 million barrels per day, according to OilPrice.com.