BAGHDAD - At least two rockets hit Baghdad's fortified Green Zone early on Thursday but caused no casualties, Iraqi security sources said.

One senior Iraqi security official said the rockets were launched from a mainly Shi'ite neighbourhood in eastern Baghdad and initial investigations indicate the rockets were targeting the U.S. embassy, but fell short.

One rocket landed in a parking lot inside the Green Zone and a second one hit a nearby empty area, said the sources.

Thursday's attack comes two days after U.S. President Joe Biden and Iraqi Prime Minister Mustafa al-Kadhimi sealed an agreement on Monday formally ending the U.S. combat mission in Iraq by the end of 2021.

Prime Minister Kadhimi has been facing increasing pressure from Iran-aligned parties and paramilitary groups who oppose the U.S. military role in the country.

U.S. diplomats and troops in Iraq and Syria were targeted in three rocket and drone attacks earlier this month, including one in which at least 14 rockets hit an Iraqi air base hosting U.S. forces. Two U.S. service members were wounded.

While there were no immediate claims of responsibility for the attacks - part of a wave targeting U.S. troops or areas where they are based in Iraq and Syria - analysts believed they were part of a campaign by Iranian-backed militias.

The Green Zone hosts foreign embassies and government buildings and is regularly the target of rockets fired by groups that U.S. and Iraqi officials say are backed by Iran.

(Reporting by Ahmed Rasheed; Editing by Raissa Kasolowsky) ((ahmed.rasheed@thomsonreuters.com; +964-7901-947-131; Reuters Messaging: ahmed.rasheed.thomsonreuters.com@thomsonreuters.net))