Legal battles are playing out across the US as opponents of President Donald Trump's travel ban on citizens from seven predominantly Muslim nations take their fight to the courtroom.

Hearings were held this week in a few of the cases.

The following looks at some of the court challenges:

VIRGINIA

A judge is allowing Virginia to join a lawsuit challenging the travel ban.

Friday's ruling by US District Judge Leonie Brinkema greatly expands the scope of the lawsuit, which was initially focused only on legal permanent residents, commonly called green-card holders. Judge Brinkema indicated a willingness to consider cases involving anyone who had been issued a visa and had it revoked.

A government lawyer in the case said more than 100,000 people have had visas revoked since the ban went into effect, but the State Department later said the number was close to 60,000. The higher figure included visas that were actually exempted by the travel ban, as well as expired visas.

MASSACHUSETTS

A federal judge in Boston has declined to extend a temporary injunction against President Donald Trump's travel ban.

US District Judge Nathaniel Gorton refused to renew an order prohibiting the detention or removal of persons as part of Trump's executive order on refugees and immigrants.

That means the seven-day, temporary injunction granted 29 January will expire as scheduled Sunday.

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HAWAII

Hawaii is suing the federal government to stop President Donald Trump's travel ban on people from seven majority Muslim countries.

Attorney General Doug Chin says Mr Trump's executive order keeps Hawaii families apart and keeps residents from travelling. He says it degrades values Hawaii has worked hard to protect.

Mr Chin says the order also will make foreign travellers feel unwelcome, which is a problem for Hawaii's tourism-powered economy.

Hawaii filed the lawsuit in federal court in Honolulu on Friday.

WASHINGTON

A federal judge in Seattle has temporarily blocked President Donald Trump’s executive order banning entry into the United States from seven Muslim-majority countries.

US District Judge James Robert, who was appointed by President George Bush in 2003, issued a temporary restraining order against the Trump administration's restrictions, ruling that the ban would be immediately stopped nationwide.

Minnesota has joined Washington state in seeking a temporary restraining order.

NEW YORK

A Brooklyn judge on Thursday extended a temporary restraining order to 21 February, but the Justice Department said it will ask for the case to be thrown out.

US District Judge Carol Amon's ruling extended a stay that had been issued Saturday by a different judge and would have expired on 11 February. Judge Amon extended the order to give more time the government and civil liberties organisations to file paperwork.

Donald Trump fights back after judge blocks his travel ban

MICHIGAN

A federal judge in Detroit says US green-card holders shouldn't be affected by the order.

The Arab-American Civil Rights League argued in a suit filed this week in Detroit's US District Court that the executive action is unconstitutional and targets immigrant communities.

A restraining order released Friday from US District Judge Victoria Roberts covers legal permanent residents, not some others that also are part of the lawsuit. She says lawyers for the government clarified to her that the ban doesn't apply to "lawful" permanent residents.

CALIFORNIA

Three California university students are challenging the ban. Their federal suit, filed Thursday in San Francisco, says the ban is unconstitutional and has created hardships for the students.

It alleges that a freshman at Stanford University now can't visit her husband in Yemen; another Yemeni at San Diego's Grossmont College can't resume studies there; and an unidentified University of California Berkeley doctoral candidate from Iran fears losing a job opportunity.